Issued 14 July 2023

June 2023 Palmer Z-Index
U.S. Percent Area Wet or Dry January 1996 - June 2023
June 2023 /monitoring-content/sotc/drought/2023/06/mo-p-reg023dv00elem01-04062023.gif

Please note that the values presented in this report are based on preliminary data. They will change when the final data are processed, but will not be replaced on these pages.

National Drought Highlights

Detailed Drought Overview

The upper-level atmospheric circulation over North America during June 2023 consisted of a battle between an upper-level ridge and migrating shortwave troughs and closed lows. High pressure extended across low latitudes, with cells over the Atlantic and Mexico. The ridge over North America extended northward from the Mexico high pressure cell. Upper-level troughs and lows moving in the jet-stream flow ran into the ridge. At times they stalled out when the ridge was more powerful, while at other times during the month they were able to penetrate the ridge. They frequently took up residence in the southwestern U.S. and in the East. When the upper-level circulation is averaged across the month, the pattern consisted of a ridge across the central CONUS, extending from Mexico into central Canada, and troughs along the west and east coasts. The monthly temperature anomaly pattern reflected this, with cooler-than-normal temperatures in the Southwest and east of the Mississippi River associated with the troughs, and warmer-than-normal temperatures in the southern Plains, Pacific Northwest, and northern Plains to Upper Mississippi Valley associated with the ridge. Puerto Rico and the U.S. Virgin Islands were also warmer than normal beneath the North Atlantic cell of the high pressure ridge.

Cool fronts and surface low pressure systems were associated with the troughs and closed lows. The fronts frequently swept across the eastern CONUS, reinforcing the below-normal temperatures. In the West, the fronts, troughs, and lows tapped Pacific and Gulf of Mexico moisture to spread above-normal precipitation across an area from southern California to the central and northern Rockies. In the East, they tapped Gulf and Atlantic moisture to spread above-normal precipitation across parts of the Plains, southern Mississippi Valley, Southeast, and northern New England. Severe weather accompanied these systems, especially east of the Rockies. The ridge inhibited precipitation elsewhere, with monthly precipitation below normal across most of the West Coast, parts of the Pacific Northwest, much of the Southwest to southern Plains and western Gulf of Mexico coast, eastern portions of the central Plains to the Great Lakes and central Appalachians, and parts of the Mid-Atlantic Coast to southern New England. Several large wildfires developed over the Southwest (wildfire maps for June 1, 27, 30). The dryness was especially severe from Missouri to the Great Lakes and extended into Canada, where hundreds of large wildfires burned throughout the month. Northern parts of Puerto Rico and the U.S. Virgin Islands were drier than normal beneath the North Atlantic cell of the high pressure ridge. The low-latitude high-pressure ridge extended across the Pacific, contributing to a drier-than-normal month for much of Hawaii, while frequent troughing over Alaska gave the state a cooler-than-normal month with a mixed precipitation anomaly pattern.

The above-normal precipitation resulted in contraction or reduction of the intensity of drought over parts of the Pacific Northwest, Great Basin, Rocky Mountains, Florida, and Northeast, and much of the western Great Plains. Drought or abnormal dryness also contracted from eastern Tennessee to Ohio where showers frequently developed. June temperatures were much warmer than normal over the northern Plains, parts of the Pacific Northwest, and from southern New Mexico to the Lower Mississippi Valley. The heat was especially persistent and extreme in the South. The unusually warm temperatures increased evapotranspiration which exacerbated conditions where precipitation was below normal. Drought or abnormal dryness intensified or expanded over other parts of the Pacific Northwest, across the western Gulf of Mexico coast, over the eastern Great Plains to Mid-Mississippi Valley and Great Lakes, in a few parts of the Northeast, and over parts of Puerto Rico, Hawaii, and Alaska. Drought expansion exceeded contraction with the USDM-based national moderate-to-exceptional drought footprint across the CONUS increasing from 19.0% at the end of May to 27.0% at the end of June (from 15.8% to 22.6% for the 50 states and Puerto Rico).

According to the Palmer Drought Index, which goes back to the beginning of the 20th century, about 19.0% of the CONUS was in moderate to extreme drought at the end of June, which is an increase compared to the end of May.

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Drought conditions at the end of June, as depicted on the July 4, 2023 USDM map, included the following core drought and abnormally dry areas:

June 2023 /monitoring-content/sotc/drought/2023/06/20230704_usdm.png

Palmer Drought Index

The Palmer drought indices measure the balance between moisture demand (evapotranspiration driven by temperature) and moisture supply (precipitation). The Palmer Z Index depicts moisture conditions for the current month, while the Palmer Hydrological Drought Index (PHDI) and Palmer Drought Severity Index (PDSI) depict the current month's cumulative moisture conditions integrated over the last several months.

While both the PDSI and PHDI indices show long-term moisture conditions, the PDSI depicts meteorological drought while the PHDI depicts hydrological drought. The PDSI map may show less severe and extensive drought (as well as wet spell conditions) in some parts of the country than the PHDI map because the meteorological conditions that produce drought and wet spell conditions are not as long-lasting as the hydrological impacts.

June 2023 Palmer Z-Index
June 2023 PHDI

Used together, the Palmer Z Index and PHDI maps show that short-term drought occurred in the Pacific Northwest Coast, Lower Mississippi Valley, and in Texas along the Rio Grande Valley, expanding or intensifying long-term drought (PHDI maps for June compared to May), and from eastern parts of the Plains to the Great Lakes, eliminating remnant long-term wet conditions and introducing long-term dry conditions. Short-term wet conditions occurred in the Southeast, parts of the Northeast, the northern to central Rockies, and in western parts of the Great Plains, contracting or reducing the intensity of long-term drought and introducing areas of long-term wet conditions, and in the Southwest, intensifying long-term wet conditions.

Standardized Precipitation Index

The Standardized Precipitation Index (SPI) measures moisture supply. The SPI maps here show the spatial extent of anomalously wet and dry areas at time scales ranging from 1 month to 24 months.

June 2023 SPI
May-June 2023 SPI
April-June 2023 SPI
January-June 2023 SPI

The SPI maps illustrate how moisture conditions have varied considerably through time and space over the last two years. Dryness is evident across the Great Lakes and much of the Mississippi and Ohio Valleys and Northeast at the 1- to 3-month time scales; the central Appalachians to Mid-Atlantic and southern parts of the Northeast at 2 to 9 months; in the Mid-Atlantic at 12 to 24 months; and in parts of the Pacific Northwest at 1, 2, and 6-12 months. Eastern parts of the Great Plains are dry at all time scales, with most of the central to southern Great Plains dry at the 24-month time scale. The Rio Grande Valley and western Gulf of Mexico Coast are dry at the 1-month time scale, with parts of the Lower Mississippi Valley dry at all time scales. Parts of the Southwest are dry at 1, 3, and 6 months. Much of the West is wet at 1-2 and 6-24 months; western parts of the Great Plains are wet at 1- to 9-month time scales with northern parts of the Plains wet at 24 months; and parts of the Southeast and northern New England are wet at all time scales.

October 2022-June 2023 SPI
July 2022-June 2023 SPI
July 2021-June 2023 SPI

Standardized Precipitation Evapotranspiration Index

The SPI measures water supply (precipitation), while the SPEI (Standardized Precipitation Evapotranspiration Index) measures the combination of water supply (precipitation) and water demand (evapotranspiration as computed from temperature). Warmer temperatures tend to increase evapotranspiration, which generally makes droughts more intense.

For the Northern Hemisphere, June marks the beginning of climatological summer, which is the season when evapotranspiration reaches its annual maximum. During June 2023, temperatures were warmer than normal for parts of the Pacific Northwest, northern and southern Plains, and northern and southern Mississippi Valley. Some of these areas were drier than normal, but most of the Midwest (which was much drier than normal) had temperatures that were generally near to cooler than normal. As a result, the June SPEI was a little more severe than the June SPI over parts of Texas, the SPI was a little more severe than the SPEI over parts of the Midwest, and the SPI and SPEI were very similar for the rest of the CONUS. The temperature anomaly pattern for May-June was similar to that for June, so the May-June SPEI was a little more severe than the SPI in the Pacific Northwest, where it was dry, but not elsewhere. With temperatures for the last 3 and 4 months near to cooler than normal over the dry areas, the SPI was actually more severe than the SPEI over the dry areas. A similar situation was seen for most areas for the last 12 months, except in the Pacific Northwest at the 12-month time scale (SPEI maps for the last 1, 2, 3, 4, 6, 9, 12 months) (SPI maps for the last 1, 2, 3, 4, 6, 9, 12 months).

The May-June SPEI for Washington state was more extreme than the corresponding 2-month SPI. But the opposite was true for the Midwest. While both were severe, the 2-month SPEI for Wisconsin was not as severe as the corresponding SPI, and the April-June SPEI for Missouri was about as severe as the corresponding 3-month SPI.

The last 2 to 3 years have been extremely dry in the central Plains — so dry, in fact, that the SPI is more extreme than the corresponding SPEI in spite of temperatures being above normal (24-month temperature ranks, precipitation ranks, SPEI, SPI) (36-month temperature ranks, precipitation ranks, SPEI, SPI). In the southern Plains (Texas), the temperature anomalies were hot enough to make the SPEI more extreme than the SPI at these time scales.

For the western U.S., the last 12 months have seen temperatures that were near the long-term average, but most of the last 10 to 20 years have been a period of unusually warm temperatures across the West. There have also been periods of extreme dryness westwide during this period (this year being an exception). The combination of excessive heat and dryness has resulted in more extreme SPEI values than SPI values for the last 2 to 6 years (SPEI maps for last 24, 30, 36, 48, 60, 72 months) (SPI maps for last 24, 30, 36, 48, 60, 72 months).

Regional Discussion

Midwest United States

The last 1 to 3 months have been extremely dry across the Upper Mississippi Valley, Great Lakes, and Ohio Valley region. This area is represented by two climate regions — the East North Central region (Upper Midwest) and Central region (Ohio Valley). The East North Central region had the eighth driest June in the 1895-2023 record, third driest May-June, and ninth driest April-June. The Central region had the 14th driest June, ninth driest May-June, and seventh driest April-June. On a statewide basis, several states had the tenth driest, or drier, June, May-June, and April-June.

Great Plains

Western parts of the Great Plains received above-normal precipitation during June 2023 while eastern and southern portions were drier than normal. This continued a pattern that has been happening for the last 2 to 3 months. These short-term wet conditions helped lessen precipitation deficits, but long-term deficits still remain. Regionwide, the Great Plains had:

As of the end of June, 25.6% of the Great Plains region was affected by moderate to extreme drought, based on the PDSI. This is less than the end of May. The recent drought, at its peak last year, was as expansive as the drought of the 1950s. The temperatures that occurred with the recent drought have been as hot or hotter than the peak temperatures of the 1950s drought and most of the 1930s drought.

While rain has been falling in western parts of the Plains, eastern parts have continued dry. Eastern Nebraska and parts of Kansas are now the epicenter of the Plains drought. Parts of eastern Nebraska have had record dry conditions as measured by the SPI:

Hawaii

Drier-than-normal conditions dominated most of the stations across the main Hawaiian Islands during June 2023. May-June had a mixed precipitation anomaly pattern, with drier-than-normal conditions dominating the windward side of the Big Island and some stations on Maui and Oahu. The last 3 to 4 months were mostly wetter than normal, except for the windward side of the Big Island and Maui. Wetter-than-normal conditions dominated at 6-9 months. At longer time scales, parts of the Big Island and Oahu were drier than normal,with a mixed pattern evident at 60 months (precipitation anomaly maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (climate engine model percent of normal precipitation map for the last month).

Monthly streamflow was below normal on Maui and the Big Island but near to above normal on Molokai, Oahu, and Kauai. Based on satellite analyses (stressed vegetation, drought stress, VHI), there were areas of vegetative stress this month on Maui and the Big Island, some stress developing on Molokai and Oahu.

Moderate drought returned to Hawaii during June, covering about 10.2% of the state on the July 4, 2023 USDM map.

Alaska

June 2023 had a mixed precipitation anomaly pattern, with drier-than-normal conditions dominating in eastern areas and across most of the Aleutians. Drier-than-normal areas were evident in the west and south central (Cook Inlet and Northwest Gulf) regions and along the Aleutians at the 3-month time scale, and in the south central and Aleutian regions at 4- to 48-month time scales (low elevation station precipitation anomaly maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (high elevation SNOTEL station precipitation percentile maps for the last 1, 3, 6, 9, and 12 months) (SNOTEL basin and station percent of normal precipitation maps for the last 1, 3, 6, 9, and 12 months) (climate division precipitation rank maps for the last 1, 3, 6, and 12 months) (climate engine model percent of normal precipitation map for the last month) (Leaky Bucket model precipitation percentile map).

June temperatures were warmer than normal in the Aleutians and in parts of the North Slope and the Southeast, while below-normal temperatures dominated in the interior to western areas. Cooler-than-normal temperatures were the rule at the 2- to 4-month time scales. Temperatures were warmer than normal along the northern, eastern, and southern peripheries of the state at 6 months. Warmer-than-average temperatures dominated at longer time scales, when compared to the long-term (1926-2022) average. But when compared to more recent (1991-2020) normals, near to cooler-than-normal temperatures were evident at some western to central stations because of a pronounced warming trend in recent decades (low elevation station temperature anomaly maps for the last 1, 2, 3, 4, 6, 9, 12 months) (climate division temperature rank maps for the last 1, 3, 6, and 12 months) (gridded temperature percentile maps for the last 1, 3, and 6 months) (Leaky Bucket model temperature percentile map).

Monthly streamflow was mostly near to above normal. Satellite observations of vegetative health (stressed vegetation, drought stress, VHI) revealed a few areas of drought-related stress. Satellite-based observations of groundwater and soil moisture (GRACE root zone, GRACE surface, SMOS soil moisture, Leaky Bucket modeled soil moisture) suggested some dryness was occurring in the south and east.

Areas of abnormal dryness developed during June in the south and east, with a small area of moderate drought in northeast Alaska. Only 0.2% of the state was in drought, and abnormal dryness and drought covered only 2.1% of the state, on the July 4, 2023 USDM map.

Puerto Rico and U.S. Virgin Islands

June 2023 was drier than normal across northern portions of Puerto Rico (PR) and the U.S. Virgin Islands (USVI). The last 2 months were drier than normal across most of PR and the USVI. PR had a mixed precipitation anomaly pattern at the 3- to 9-month time scales, with dry conditions mostly in the north and wet conditions in the south, while the USVI were consistently dry during this period. PR was mostly wetter than normal at 12 months while the USVI had a mixed anomaly pattern. Drier-than-normal conditions became progressively more widespread at longer time scales (radar-based precipitation anomaly estimates for the last 1, 2, 3, and 6 months) (low elevation station precipitation anomaly maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months) (climate engine model percent of normal precipitation map for the last month: PR and USVI, Caribbean and Gulf of Mexico region). Temperatures were consistently warmer than normal, especially for the last 1 to 3 months (low elevation station temperature anomaly maps for the last 1, 2, 3, 4, 6, 9, 12 months). The Rohlsen Airport station on St. Croix had the third warmest June in the 1951-2023 historical record, and seventh driest March-June, third driest February-June, third driest January-June, and driest December-June (not counting years with too much missing data).

Root zone analyses indicated that soil conditions were moist across eastern coastal and interior portions of western to central PR, but dry along the southern and northern coasts and a strip over eastern PR (root zone soil saturation fraction). Monthly streamflow on PR showed a mix of below-normal and near-normal streams across the island. In the USVI, for the most part, groundwater steadily declined during June at St. Croix, St. John, and St. Thomas, although it rose in response to beneficial rains the last day of the month at St. Croix and St. Thomas. The end-of-June groundwater level was in mid-range (below previous peaks and above recent low levels) on all three islands (St. Thomas, St. Croix, St. John), although the St. Croix value was well into the bottom third of the historical record. Significant drought impacts have been received from the USVI through the National Integrated Drought Information System (NIDIS). These include: Lack of rainfall, high winds and high temperatures have reduced the moisture in the soil, ponds are drying out, and several dozen animals succumbed to a combination of heat, lack of water and access to grazing. The Dorothea well on St. Thomas was reportedly "slowed to a trickle and smelling like salt, so we think it is running very low."

Drought conditions remained unchanged in the USVI, with extreme drought continuing on St. Croix, severe drought persisting on St. Thomas, and moderate drought continuing on St. John. Moderate to severe drought expanded to cover about 7.4% of PR on the July 4, 2023 USDM map.

CONUS State Precipitation Ranks

June 2023 was drier than normal across much of the region from the eastern Great Plains to Great Lakes, the Southwest to western Gulf of Mexico Coast, and West Coast, and parts of the Mid-Atlantic to southern New England, with record dryness occurring in parts of the Southwest. Thirteen states had a precipitation rank in the driest third of the 129-year historical record for June, including four that ranked in the top ten driest category — Wisconsin and Michigan (both fifth driest), Missouri (sixth driest), and Illinois (ninth driest).

The last two months (May-June 2023) were drier than normal from eastern portions of the central and northern Plains to the Mid-Atlantic and New England coast, and parts of the Pacific Northwest, Southwest, and western Gulf of Mexico coast. Twenty states had a precipitation rank in the driest third of the 1895-2023 historical record for May-June, including seven that ranked in the top ten driest category — Wisconsin (third driest), Michigan (fifth driest), Illinois (seventh driest), Missouri and Minnesota (both eighth driest), Iowa (ninth driest), and Indiana (tenth driest) — and two that were close — Maryland and Washington (both eleventh driest).

April-June 2023 was drier than normal across much of the region from the eastern Great Plains to Great Lakes and Ohio Valley, central Appalachians to southern New England and Mid-Atlantic Coast, West Coast, and Southwest, and parts of the Pacific Northwest and western Gulf of Mexico Coast, with record dryness occurring in parts of the Midwest. Sixteen states had a precipitation rank in the driest third of the historical record for April-June, including five that ranked in the top ten driest category — Missouri (fourth driest), Illinois (sixth driest), Iowa (seventh driest), Indiana (ninth driest), and Wisconsin (tenth driest).

The year-to-date (January-June 2023) was drier than normal across eastern portions of the central and northern Plains to the southern Great Lakes and Ohio Valley, from the central Appalachians to southern New England and Mid-Atlantic Coast, in parts of the Pacific Northwest and Southwest to Texas, and along the Gulf of Mexico Coast, with record dryness occurring in parts of the Mid-Atlantic. Thirteen states had a precipitation rank in the driest third of the historical record for January-June, including one that ranked in the top ten driest category — Maryland (fourth driest).

July 2022-June 2023 was drier than normal across much of the Great Plains, Midwest, Mid-Atlantic Coast to southern New England, and Pacific Northwest, with record dryness occurring in parts of the central Plains. Fifteen states had a precipitation rank in the driest third of the historical record for July-June, including one that ranked in the top ten driest category — Kansas (ninth driest) — and two that were close — Washington (13th driest) and Iowa (14th driest).

Agricultural Belts

During June 2023, the Primary Corn and Soybean agricultural belt was drier than normal with warmer-than-normal temperatures in the northwest and cooler-than-normal temperatures in the southeast. The month ranked as the sixth driest and 42nd warmest June, regionwide, in the 1895-2023 record.

March marks the beginning of the growing season for the Primary Corn and Soybean agricultural belt. March-June 2023 was mostly drier than normal and near to cooler than normal. The period ranked as the 16th driest and 46th warmest March-June, regionwide.

The last three months have been especially dry for the Primary Corn and Soybean belt with temperatures mostly near to warmer than normal. The period ranked as the fourth driest and 37th warmest April-June, regionwide.

According to the U.S. Department of Agriculture (USDA), as of July 4, 2023, drought affected approximately 12% of barley production, 67% of corn production, 18% of cotton production, 55% of sorghum production, 60% of soybean production, 19% of spring wheat production, 54% of winter wheat production, 31% of hay acreage, 41% of the cattle inventory, 38% of the milk cow inventory, and 27% of the sheep inventory. Based on July 2 USDA statistics, 29% of the nation's winter wheat crop, 15% of the corn crop, 15% of the soybean crop, 12% of the spring wheat crop, and 25% of the nation's pasture and rangeland were in poor to very poor condition, and 42% of the nation's topsoil and 48% of the subsoil were short or very short of moisture (dry or very dry). The table below lists the soil moisture, pasture and rangeland, corn, soybean, spring wheat, and winter wheat condition by state, with those states having 30 percent or more of topsoil or subsoil moisture short or very short, or 30 percent or more of the crop or pasture and rangeland in poor or very poor condition, highlighted in yellow:

Statewide topsoil moisture, subsoil moisture, and crop condition

U.S.-Affiliated Pacific Islands

The NOAA National Weather Service (NWS) offices, the Pacific ENSO Applications Climate Center (PEAC), and partners provided reports on conditions across the Pacific Islands.

In the U.S. Affiliated Pacific Islands (USAPI) (maps — Federated States of Micronesia [FSM], Northern Mariana Islands, Marshall Islands [RMI], Republic of Palau [ROP], American Samoa, basinwide), June 2023 was drier than normal in Palau and the northern Marianas, and near to wetter than normal everywhere else.

Monthly precipitation amounts were below the monthly minimum needed to meet most water needs (4 inches in the Marianas and Pago Pago, and 8 inches elsewhere) at Wotje (RMI), Fananu (FSM), and Rota and Saipan (Marianas). June precipitation was above the monthly minimums at the rest of the stations across the USAPI. The 4- and 8-inch thresholds are important because, if monthly precipitation falls below the threshold, then water shortages or drought become a concern.

The tropical Pacific climatology can experience extremes in precipitation, from very low precipitation during the dry season to very high precipitation during the wet season. This can result in monthly normal precipitation values that are different from the monthly minimum needed to meet most water needs, and this can lead to percent of normal values that seem odd. This was the case during June 2023, which is in the wet season for the Palau and parts of the FSM and Marianas and dry season for American Samoa. Precipitation was below the monthly minimum but above normal (1981-2010 normal), because the normals are low, at:

Precipitation was above the monthly minimum but below normal (1981-2010 normal), because the normals are high, at:

  • Airai: June 2023 precipitation 13.44 inches, June normal mean 18.01 inches, June normal median 17.48 inches.
  • Jaluit: June 2023 precipitation 8.97 inches, June normal mean 10.37 inches.

In the table below, the station identified as Koror is Palau International Airport (Airai).

Pacific Island Percent of 1981-2010 Normal Median Precipitation
Station Name Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr
2023
May
2023
Jun
2023
Jul-
Jun
Chuuk107%70%121%124%93%116%92%215%85%137%191%118%115%
Guam NAS135%62%109%150%77%182%350%188%263%198%916%146%140%
Kapingamarangi61%51%44%34%55%53%166%47%116%141%137%145%82%
Koror72%119%45%241%88%105%187%102%185%77%165%77%108%
Kosrae169%117%134%169%107%99%131%188%67%120%87%166%107%
Kwajalein94%132%68%161%81%88%224%50%189%188%345%143%131%
Lukonor66%32%36%95%94%54%124%68%96%77%61%116%65%
Majuro96%74%159%147%91%90%157%138%169%151%102%105%118%
Pago Pago166%121%60%149%118%71%114%110%106%152%168%109%104%
Pohnpei173%138%143%148%85%74%136%146%109%141%145%121%126%
Saipan159%80%67%151%60%130%441%118%138%192%225%92%123%
Yap110%65%57%217%68%131%133%118%137%104%131%121%107%
Pacific Island Precipitation (Inches)
Station Name Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr
2023
May
2023
Jun
2023
Jul-
Jun
Chuuk12.86"8.98"14.15"14.27"9.83"13.00"9.34"15.60"7.09"17.14"21.57"13.73"157.56"
Guam NAS13.71"9.15"13.74"17.12"5.66"9.32"14.02"5.69"5.45"5.01"31.15"9.00"139.02"
Kapingamarangi8.60"4.17"4.38"2.76"5.11"5.23"15.23"4.37"13.24"19.19"16.59"20.04"118.91"
Koror13.31"16.00"5.26"28.49"10.00"11.76"19.04"8.74"13.74"5.60"19.53"13.44"164.91"
Kosrae25.14"16.69"19.11"18.53"14.74"15.95"21.87"24.25"10.81"21.08"15.41"24.30"227.88"
Kwajalein9.23"12.81"7.34"18.02"9.09"5.88"7.08"1.32"4.43"9.87"23.18"9.93"118.18"
Lukonor10.52"4.55"3.70"10.73"8.52"6.06"10.45"6.08"8.92"8.68"7.13"13.55"98.89"
Majuro10.70"8.65"17.72"18.76"12.21"10.30"12.14"9.51"11.12"14.23"10.35"11.56"147.25"
Pago Pago9.23"6.53"3.92"13.82"11.93"9.10"15.19"13.19"11.34"14.25"16.19"5.81"130.5"
Pohnpei26.66"19.69"17.91"22.62"12.66"11.86"17.94"13.99"14.29"25.90"29.02"17.94"230.48"
Saipan14.16"10.55"6.72"16.07"3.39"5.01"11.16"3.05"2.61"5.05"5.35"3.34"86.46"
Yap16.54"9.57"7.76"26.48"5.99"11.17"8.51"6.11"6.26"5.86"10.28"14.59"129.12"
Pacific Island 1981-2010 Normal Median Precipitation (Inches)
Station Name Jul
2022
Aug
2022
Sep
2022
Oct
2022
Nov
2022
Dec
2022
Jan
2023
Feb
2023
Mar
2023
Apr
2023
May
2023
Jun
2023
Jul-
Jun
Chuuk11.98"12.86"11.71"11.51"10.61"11.25"10.10"7.25"8.32"12.47"11.30"11.66"136.77"
Guam NAS10.14"14.74"12.66"11.44"7.38"5.11"4.01"3.03"2.07"2.53"3.40"6.18"99.09"
Kapingamarangi14.15"8.13"9.93"8.19"9.27"9.84"9.15"9.27"11.43"13.64"12.08"13.78"145.85"
Koror18.53"13.50"11.77"11.84"11.39"11.16"10.18"8.56"7.44"7.32"11.83"17.48"152.90"
Kosrae14.91"14.22"14.22"10.94"13.83"16.11"16.67"12.93"16.06"17.51"17.75"14.64"213.87"
Kwajalein9.87"9.74"10.74"11.18"11.28"6.66"3.16"2.64"2.35"5.26"6.72"6.93"90.41"
Lukonor15.93"14.04"10.15"11.32"9.08"11.27"8.41"8.93"9.26"11.31"11.69"11.65"151.36"
Majuro11.17"11.69"11.17"12.73"13.44"11.39"7.74"6.88"6.58"9.42"10.11"11.01"125.25"
Pago Pago5.55"5.38"6.53"9.26"10.14"12.84"13.34"12.00"10.68"9.39"9.66"5.33"125.57"
Pohnpei15.43"14.26"12.55"15.27"14.83"16.08"13.18"9.55"13.17"18.41"19.96"14.81"182.36"
Saipan8.91"13.13"10.09"10.62"5.61"3.85"2.53"2.59"1.89"2.63"2.38"3.62"70.25"
Yap15.08"14.82"13.50"12.18"8.83"8.51"6.39"5.19"4.56"5.63"7.85"12.04"120.31"

As measured by percent of normal precipitation, no station was drier than normal in the short term (June, the last 3 months [April-June], and the year-to-date [January-June]) and long term (last 12 months [July 2022-June 2023]). Lukunor was drier than normal for 3 of the time periods and wetter than normal for June. Airai was drier than normal for June and the last 3 months but near to wetter than normal for the year to date and 12-month periods. Saipan was drier than normal for June but wetter than normal for the other 3 time periods. Kapingamarangi was drier than normal at the 12-month time scale, but wetter than normal for the other 3 time scales. Chuuk, Guam, Kosrae, Kwajalein, Majuro, Pago Pago, Pohnpei, and Yap were near to wetter than normal for all 4 time periods.

Based on percent of normal average (instead of normal median values), in the Marianas Islands, precipitation during June was above normal on Guam but drier than normal on the islands to the north. The last 2 to 24 months were mostly above normal across the main islands. Longer time periods had a mixed anomaly pattern but were mostly above normal (percent of normal precipitation maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months).

Based on percent of normal average (instead of normal median values), in the Marshall Islands, June was drier than normal in the northeast (Wotje) and southwest (Jaluit), with wetter-than-normal conditions across the rest of the RMI stations. Wetter-than-normal conditions dominated the RMI except of the southwest (Jaluit) at longer time scales (percent of normal precipitation maps for the last 1, 2, 3, 4, 6, 9, 12, 24, 36, 48, 60 months).

According to the June 30 USDM produced for the USAPI, all of the USAPI stations are free of drought and abnormal dryness. The reservoir level on Majuro steadily increased throughout the month. It began the month at 24.0 million gallons, reached a maximum of 31.1 million gallons on the 22nd and 23rd, and ended the month at 29.7 million gallons. This is above the threshold of concern for drought of 28.8 million gallons. For the past several months, one sector of the reservoir has been serviced. This portion of the reservoir system typically holds 8 million gallons, so the threshold reservoir level is lower than it normally would be.

June 2023 precipitation ranks were mostly on the median to wet side of the historical distribution, based on data available at the time of this report. Airai, Jaluit, and Saipan had June precipitation that was in or near the driest third of the historical record, while Mili had the wettest June based on this dataset. Record dryness or low precipitation ranks were still occurring at Kapingamarangi, Lukunor, and Jaluit at longer time scales:

  • Lukunor: 11th wettest June (in a 39-year record), but driest July-June and second driest August-June.
  • Jaluit: 14th driest June (39 years) and seventh driest August-June and eighth driest July-June.
  • Kapingamarangi: 5th wettest June (33 years), but seventh driest rank for July-June.

At the wet end of the scale:

  • Guam had the eighth wettest June (67 years) but wettest May-June through October-June.
  • Mili had the wettest rank for June (39 years), and January-June through July-June.
  • Saipan had the wettest January-June (42 years) through October-June.

The following analysis of historical data for the USAPI stations in the Global Historical Climatology Network-Daily (GHCN-D) dataset, augmented with fill-in data from the 1981-2010 Normals, helps put the current data into historical perspective by computing ranks based on the period of record. The table below lists the precipitation ranks for June 2023, January-June 2023 (last 6 months), and July 2022-June 2023 (the last 12 months). Some stations have a long period of record and their dataset is fairly complete, while other stations have a shorter period of record and the dataset has some missing data.

June 2023 USAPI Precipitation Ranks (1 = driest)
StationJune 2023Jan-Jun 2023Jul 2022-Jun 2023Period of Record
RankYearsRankYearsRankYears
Ailinglaplap3140354035371981-2023
Airai2472637257711951-2023
Chuuk4872647256721951-2023
Fananu29--4--32003-2023
Guam5967666665661957-2023
Jaluit143912398371981-2023
Kapingamarangi293323277201962-2023
Kosrae5056274527371954-2023
Kwajalein4672617163711952-2023
Lukunor29398391261981-2023
Majuro3970526954691954-2023
Mili3939393934341981-2023
Nukuoro2741314034381981-2023
Pago Pago2858455735571966-2023
Pingelap2441--37--341981-2023
Pohnpei4372687271721951-2023
Saipan1543424233341981-2023
Ulithi2839343719341981-2023
Utirik--15--9--51985-2020
Woleai3741--32--251968-2023
Wotje2839343930351981-2023
Yap5672417240721951-2023
Map of USAPIJune 2023 Precipitation (Inches)
Map of USAPI June 2023 Percent of Normal Precipitation
Map of USAPI April 2023-June 2023 Percent of Normal Precipitation
Map of USAPI January-June 2023 Percent of Normal Precipitation
Map of USAPI July 2022-June 2023 Percent of Normal Precipitation

SPI values for seven time periods for Pacific Islands, computed by the Honolulu NWS office.

SPI values for seven time periods for Pacific Islands

NOAA Regional Climate Centers

More information, provided by the NOAA Regional Climate Centers and others, can be found below.

Southeast

As noted by the Southeast Regional Climate Center, precipitation was highly variable across the Southeast in June, as is typical for this time of the year. The driest locations were located across northern portions of Alabama and Virginia, eastern North Carolina, southwest Florida, and Puerto Rico and the U.S. Virgin Islands, where monthly precipitation ranged from 2 to 6 inches (51 to 152 mm) below average (25 to 75 percent of normal). While several inches of precipitation fell across the island of Saint Croix over the last two days of the month, the year-to-date total at Henry Rohlsen Airport of 7.37 inches (187 mm) still ranks as the second driest on record (since 1951).

For the second straight month, mean temperatures in June were below average across much of the Southeast region. In contrast, mean temperatures were 1 to 2 degrees F (0.5 to 1.1 degrees C) above average across southern portions of Alabama and Georgia, and much of South Florida. Key West, FL recorded its second warmest June on record (since 1871). Remarkably, the greatest departures were found across Puerto Rico and the U.S. Virgin Islands, where temperatures were 3 to 4 degrees (1.6 to 2.2 degrees C) above average in places. San Juan, PR recorded its second warmest June on record (since 1898), while Saint Croix tied its third warmest June on record (since 1951). Extreme heat was observed across much of the Caribbean during the first half of the month. Several daily temperature records were tied or broken across Puerto Rico. The persistence of the heat was also noteworthy.

June began with about 15 percent of the Southeast region in abnormal dryness (D0), while moderate (D1) and severe (D2) drought covered less than 3 percent of the region. During the month, moderate (D1) drought emerged across extreme northern Alabama, while abnormal dryness (D0) expanded into northwest Georgia. Severe (D2) drought also emerged across extreme northern Virginia and was briefly introduced in the District of Columbia. Streamflow in the Potomac River fell to levels that may require releases from upstream reservoirs later this summer. The Virginia Department of Environmental Quality issued a drought watch advisory for the northern Piedmont, Eastern Shore, and Shenandoah Valley due to moisture deficits over the past two to four months. In contrast, pockets of abnormal dryness (D0) were eliminated across parts of Georgia and the Carolinas, while moderate (D1) and severe (D2) drought were eliminated across the western Panhandle of Florida, leaving a small area of abnormal dryness (D0) along the Sun and Cultural coasts. The combination of improvements and degradations yielded little overall change in drought coverage across the region. Low soil moisture and streamflows led to further intensification and expansion of drought across the Caribbean. Severe (D2) drought emerged in northwest Puerto Rico, while abnormal dryness (D0) expanded to the east and along the northern and southern slopes. Severe (D2) drought persisted on Saint Thomas and emerged on Saint John. Exceptional (D4) drought emerged on Saint Croix for the first time since USDM records began in the U.S. Virgin Islands in 2019.

Some dryland or non-irrigated corn was negatively impacted in places experiencing larger moisture deficits and warmer temperatures, particularly northern Alabama, central Georgia, and Florida, while drought stress and overgrazing were noted in parts of Virginia and Florida that missed out on much of the precipitation during the month. Across the Caribbean, farmers reported significant vegetation stress, soil moisture deficits, and water supply issues. Numerous livestock deaths were reported due to extreme heat, lack of water, and feed shortages. Producers on Saint Croix have qualified for direct assistance through the USDA's Livestock Forage Program.

South

As explained by the Southern Regional Climate Center, precipitation was below normal for much of the southern and northeastern portions of the Southern region during June, while heat returned with widespread high temperatures and records being set. Above-normal temperatures were common in the southern portions of the region and below-normal temperatures in the north and east, particularly Tennessee. Precipitation was well above normal for western Oklahoma, the Texas Panhandle, extreme northeast Texas, southern Arkansas, and central Mississippi. Statewide average precipitation totals were below normal for Texas (34th driest), Louisiana (42 driest), the Southern region as a whole (47th driest), and Tennessee (53rd driest).

During June, the spatial extent and intensity of drought saw improvements in the Texas Panhandle, western Oklahoma, and portions of central Tennessee, while conditions along the southeast Louisiana Gulf Coast, central Texas, and deep south Texas saw worsening drought conditions during June. Areas of extreme and exceptional drought, according to the USDM, persist in north central Oklahoma and near San Antonio, Texas. Much of the eastern portion of the region, eastern Texas, the Texas Panhandle, and eastern Oklahoma largely remain drought free. Despite improvements in drought status in many areas, areas that have experienced substantial drought continue to see impacts, particularly in the agriculture sector. As of July 2nd, the percentage of land with short to very short topsoil moisture in Texas and Louisiana was 70 percent and 55 percent. Pasture and rangelands in Texas, Arkansas, and Louisiana continued to show stress with only 26 percent, 38 percent, and 39 percent being rated as good to excellent.

Midwest

As described by the Midwest Regional Climate Center, June precipitation totaled 2.6 inches (66 mm) for the Midwest, which was 1.94 inches (49 mm) below normal, or 57 percent of normal, while the average June temperature for the Midwest was 69.3 degrees F (20.7 degrees C), which was 0.3 degrees F (0.2 degrees C) above the 1991-2020 normal. Temperatures were up to 5 degrees F (2.8 degrees C) above normal in the northwest and up to 4 degrees F (2.2 degrees C) below normal in the southeast.

Based on preliminary rankings, the Midwest had the 5th driest June since 1895. All nine Midwestern states measured below-normal precipitation, with totals ranging from 0.2 inch (5 mm) below normal in Kentucky to 2.71 inches (69 mm) below normal in Illinois. Preliminary rankings indicate Wisconsin was tied for the 5th driest June on record, while Missouri was tied for 7th driest. Illinois had the 10th driest June since 1895. A large portion of the Midwest had less than 50 percent of normal precipitation in June, with patchy areas of 10-25 percent of normal precipitation. Charles City, Iowa, had its driest June in 131 years, with just 0.37 inch (9.4 mm) of precipitation for the month. Hasting, Michigan, had its driest June in 120 years of observations. Minneapolis-St. Paul had the 2nd driest June in 151 years. Muskegon, Michigan, had the 3rd driest June in 124 years. Notably, numerous locations in Illinois, Indiana, Michigan, Ohio, and Wisconsin exceeded 20 consecutive days without precipitation from May into early June. Knoxville and Galesburg, Illinois, went 27 days without rainfall from May 15 to June 10. Conversely, central Kentucky had near- to above-normal precipitation in June, with a wide swath of the region accumulating up to 7.5 inches (190.5 mm) for the month.

A lack of rainfall, low humidity, and abundant sunshine resulted in drought expansion and intensification across the Midwest in June. By month's end, about 65 percent of the region was in drought, and 26 percent was abnormally dry, according to the USDM. Drought affected all nine Midwest states. Extreme (D3) drought conditions were reported in central and northeast Missouri and southeast Iowa. A large portion of Illinois and Indiana worsened to severe drought (D2). The only locations with drought improvement in June were Kentucky and central Ohio. Elevated fire danger was widespread across Michigan for the first several weeks of June. In early June, a wildfire burned 3,600 acres in northern Michigan, prompting evacuations and closing a 5-mile stretch of Interstate 75. With just 3 days, the Indianapolis Airport had the fewest number of June days on record where the dew point temperature reached or exceeded 65 degrees F (18.3 degrees C). By late June, topsoil moisture was short to very short on over 85 percent of cropland in Illinois, Michigan, and Missouri. In those same states, corn conditions were rated poor to very poor on 25-30 percent of acres.

Northeast

As summarized by the Northeast Regional Climate Center, June was consistently cool across the Northeast and featured variable amounts of precipitation, as well as multiple rounds of reduced air quality. The Northeast experienced its 17th coolest June since records began in 1895 and June precipitation totaled 3.21 inches, 73 percent of normal. For the 12 Northeast states, precipitation ranged from 34 percent of normal in Connecticut to 118 percent of normal in Maine, the lone wetter-than-normal state. This June ranked among the 20 driest on record for five states: Maryland, eighth driest; Connecticut, ninth driest; New Jersey, 12th driest; West Virginia, 16th driest; and Pennsylvania, 19th driest. Meanwhile, Maine had its 20th wettest June.

The USDM from June 6 showed 20 percent of the Northeast in moderate drought and 47 percent as abnormally dry. During the first three weeks of June, drought and abnormally dry conditions generally persisted or deteriorated in many parts of the Northeast. Severe drought was introduced in south-central Pennsylvania and central Maryland, while moderate drought and/or abnormal dryness expanded in West Virginia, Maryland, Pennsylvania, New Jersey, New York, and Connecticut. This was due to increasing precipitation deficits, low streamflow, below-normal groundwater levels, declining soil moisture, and impacts on agriculture and water resources. The main exception was northern New England, which saw some improvement due to abundant rain. During the last week of the month, locally heavy rainfall chipped away at drought and dryness across much of the region, with drought and/or abnormal dryness contracting in the Mid-Atlantic states and New York. The USDM from June 27 showed 1 percent of the Northeast in severe drought, 24 percent in moderate drought, and 40 percent as abnormally dry. At times during June, record low 7-day streamflow and/or groundwater levels were noted in parts of West Virginia, Maryland, New Jersey, Pennsylvania, and New York. Streamflow on the Potomac River in Maryland dropped to a level low enough to require daily monitoring. The low streamflow contributed to an abundance of algae that altered the taste and smell of the drinking water in some areas. Low streamflow temporarily halted whitewater rafting activities in part of West Virginia. Falling water levels in reservoirs prompted New Jersey officials to ask residents to conserve water. Meanwhile, at least 18 water suppliers in Pennsylvania asked customers to voluntarily conserve water. Pennsylvania has seen an uptick in wildfires this year, with officials temporarily prohibiting open fires in all state forests due to the dry conditions. Burn bans were enacted in several municipalities and counties in central Pennsylvania. Dry conditions have also helped fuel wildfires in New Jersey, which had seen at least 10 major fires between January 1 and mid-June. Two large fires in June were caused by lightning, an uncommon occurrence in the state. For the week ending June 18, topsoil moisture was rated very short (the lowest rating) for 71 percent of Maryland and was rated short (the second lowest rating) for just under 50 percent of Pennsylvania and West Virginia. For the same period, pasture and range conditions were rated very poor or poor for just under half of Pennsylvania and around a quarter of Maryland. Growers in several states relied on irrigation to keep plants growing; however, it increased operation costs. In parts of Pennsylvania, emergence of some crops such as corn and soybeans was slow and issues such as uneven corn fill was observed. Farmers in Pennsylvania also noted that it was difficult for newly planted crops to establish roots and some pastures turned brown, with reduced wheat yields expected. However, the conditions were favorable for haymaking and allowed for plenty of fieldwork. In some eastern West Virginia locations, seeds failed to germinate, and grass was growing slowly. Meanwhile, growers in parts of Maryland noted stunted corn and soybean crops and slow growth of hay, with reduced yields anticipated.

High Plains

As summarized by the High Plains Regional Climate Center, the month of June was both good and bad for the High Plains region. Record precipitation greatly improved drought conditions for some, while others continued to remain dry. Drought conditions continued to intensify in the eastern portions of the region, leading to significant impacts. The dryness plaguing the central and eastern parts of the region has created lasting impacts. The lack of recharge this past winter has led to several cities implementing water restrictions in an effort to conserve the precious resource. The town of Waverly, Nebraska was forced to designate emergency restrictions due to low levels, while the outskirts of Lincoln implemented mandatory restrictions of 50 percent. Other locations like Hays, Kansas reintroduced summertime restrictions that include a ban on outdoor water use from noon to 7:00 PM.

Record to near-record warmth continued in the northern part of the region this month. The trend of above-normal precipitation in the west and below-normal to the east continued into June. The Front Range and Rocky Mountains observed record to near-record amounts, while eastern Kansas was below 25 percent of their normal.

Drought conditions were erased from the state of Colorado after this month's record precipitation, with only minimal dryness left. Drought conditions further improved in June, particularly in Kansas. Eastern Nebraska continued to remain dry, with exceptional drought (D4) observed over much of the area. Overall, abnormally dry to exceptional drought (D0-D4) was reduced by nearly seven percent in the High Plains. The steady stream of precipitation in Kansas brought relief this month. D4 was reduced by nine percent, with only small pockets remaining in the state. Nebraska experienced improvements in the west and degradation in the east. Drought is firmly entrenched across the eastern part of the state, after yet another dry month.

West

As summarized by the Western Regional Climate Center, the atmospheric pattern for much of June resembled conditions in May with persistent low pressure (cutoff lows) across the Southwest and ridging across western Canada extending into the Pacific Northwest. This drove wetter- and cooler-than-normal conditions across the Great Basin, Wyoming, and southern Montana. Warmer- and drier-than-normal conditions persisted across western Oregon, Washington, northern Idaho, and northwest Montana leading to expanded drought conditions in the region. The Southwest, southern Idaho, and southwest Montana remained cool throughout June with temperatures 2-6 degrees Fahrenheit below normal across the region. Across western Oregon, Washington, northern Idaho, and northwest and eastern Montana temperatures were 2-5 degrees Fahrenheit above normal.

Precipitation totals for June were well above normal (greater than 200 percent in many locations) across parts of California, the Great Basin, and Montana. June is one of the drier months in the Southwest so absolute precipitation values were still relatively low. Dry conditions, persisting since early May, continued for western Oregon and Washington where many places saw less than 25 percent of normal June precipitation. Walla Walla, Washington received just 0.04 inch of precipitation (3 percent of normal) and one day of measurable precipitation making it the second driest June since 1949. Along the Oregon coast, Astoria and North Bend recorded 30 percent of normal (0.70 inch) and six percent of normal (0.09 inch) June precipitation, respectively.

According to the USDM at the end of June, 15 percent of the West was in drought. All remaining areas of extreme drought (D3) were removed during June. This is the first time since April 2020 without D3 or exceptional drought (D4) in the West. One area where drought conditions expanded during June was western Oregon and most of Washington. Parts of western Oregon saw two-category drought degradations and were now in moderate drought (D1).

Alaska summary: Temperatures across most of Alaska were near normal or slightly below normal (anomalies of -1 to -3 degrees Fahrenheit) except for the North Slope where temperatures were slightly above normal. Parts of Southcentral Alaska and the North Slope saw much-above-normal precipitation while drier-than-normal conditions prevailed in parts of the interior and the southern extent of the Aleutian Islands.

Hawaii summary: Temperatures across Hawaii were generally near normal, and precipitation was below normal for most of the state. June precipitation totals were 4.38 inches (60 percent of normal) at Hilo, 3.04 inches (68 percent of normal) at Hana, and 1.02 inches (57 percent of normal) at Lihue. Dryness during June led to expansion of the extent of drought conditions across parts of the state. The USDM at the end of June showed 33 percent of the state in abnormally dry conditions (D0) and ten percent of the state in moderate drought (D1) with D1 restricted to the islands of Maui and the Big Island.

Additional Resources


Citing This Report

NOAA National Centers for Environmental Information, Monthly Drought Report for June 2023, published online July 2023, retrieved on July 22, 2024 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/drought/202306.