U.S. Annual Temperature timeseries
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National Temperatures

Based on data through the end of 2008, the contiguous U.S. experienced a nationally averaged temperature that was the coolest in more than ten years. The average temperature of 53.0°F (11.7°C) was 0.2°F (0.1°C) above the 20th century (1901-2000) mean.

The average temperature for the U.S. has not been this close to the 20th century mean since 1997. The January - December statewide temperature ranking map for 1997 display a close resemblance to the 2008 map. The anomalous warmth that the contiguous U.S. has seen the past 10 years was generally isolated within the West, Southwest, and Northeast Regions during 2008. In contrast, the Central and East North Central regions of the U.S. were below the 20th century mean. This resulted in a near normal nationally averaged temperature of 53.0°F (11.7°C).

2008 National Annual Temperature Rank Map

Seasonal Analysis:

The 2007-2008 winter season (December-February) was the 53rd warmest such period on record (1896-2008), with warmer-than-average temperatures along the South, Southeast and Northeast. Winter temperatures were below normal in the East North Central, Southwest, and West regions.

Spring 2008 (March-May) was the 45th coolest for the nation, with below average temperatures across the central Plains and westward. Rhode Island was 11th warmest on record during this period.

The contiguous U.S. experienced a warmer-than-normal summer (June-August), as the nation ranked 30th warmest in the last 114 years. Much above average temperatures were limited to the west, where California experienced their 6th warmest summer on record, and in the Northeast, where New Jersey experienced their 8th warmest summer and Rhode Island experienced their 6th warmest summer on record.

Temperature averages during the fall (September-November) for the western U.S. were above normal, while the eastern U.S. had below normal averages. California experienced the 3rd warmest fall on record. Arizona, Nevada, and Utah were much above normal during the period as well. This contrasted greatly with the South and Southeast where Georgia saw their 8th coolest fall period on record and both South Carolina and Mississippi experienced their 10th coolest fall. The resulting 2008 fall season (September-November) ranked 32nd warmest nationally.

For the January-December 2008 period, cooler-than-average temperatures affected much of the Central, East North Central, and parts of the South regions, while warmer than average temperatures affected the Southwest, West, and portions of the Northeast regions. This resulted in the 39th warmest January-December in the 114-year record nationally. New Jersey experienced their 10th warmest and Delaware had their 11th warmest annual period. Conversely, Iowa had their 11th coolest annual period.

Annual temperatures across the state of Alaska during 2008 averaged approximately 0.7°F (0.4°C) below normal. Winter temperatures in 2007-2008 were near average. Spring was the 29th warmest on record with with a temperature 1.0°F (0.6°C) above average, Summer was 1.0 °F (0.6°C) cooler than average, and Fall was more than 2.0°F (1.1°) cooler than the 1971-2000 average.

The percent area of the contiguous United States very warm and very cold during each of the past 48 months is listed in the figure to the left. These percentages are computed based on the climate division data set. Those climate divisions having the monthly average temperature in the top ten percent (> 90th percentile) of their historical distribution are very warm and those in the bottom ten percent (< 10th percentile) are very cold.

The U.S. did not see any massive warm or cold outbreaks during 2008 and only once in 2008 (November) did 20% or more of the U.S. experienced very warm monthly average temperatures.

Below average temperatures were measured in the lower troposphere for the first time in more than 10 years. Data collected by NOAA's TIROS-N polar-orbiting satellites and adjusted for time-dependent biases by NASA and the Global Hydrology and Climate Center at the University of Alabama in Huntsville, indicate that temperatures in the lower half of the troposphere (lowest 8 km of the atmosphere) over the U.S. were slightly cooler than the 20-year (1979-1998) average.

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National Precipitation

Precipitation in the United States during 2008 was variable throughout much of the country with periods of excessive rainfall, especially across the central third of the country. The western U.S. remained parched, while the drought conditions lessened in the Southeast. The Northeast region averaged 50.04 inches (1,274 mm) of precipitation in 2008 which was 9.06 inches (230 mm) above the 20th century (1901-2000) average. New Hampshire experienced their 5th consecutive year with above average precipitation with 19.84 inches (504mm). It was their wettest on record, breaking the previous record set just four years prior. Missouri also experienced their wettest year on record with 57.28 inches (1455 mm) of precipitation, which was 16.52 inches (420 mm) above average.

Precipitation during the December 2007 - February 2008 period was above normal for much of the contiguous U.S. as it was the 16th wettest winter on record. In the spring an average of 8.0 (203 mm) inches of precipitation fell across the U.S., making the season the 42nd wettest on record. California had the driest spring on record, while Nevada and Utah had their 10th and 11th driest springs on record, respectively, Missouri had their fourth wettest spring and Arkansas, Indiana and Iowa all experienced a wet period that ranked in the top 10 on record. The summer brought an average of 8.0 inches (203 mm) of precipitation across the U.S., however much of the precipitation occurred in the eastern two-thirds of the country. It was the 53rd driest fall on record for the nation. The precipitation pattern for much of the contiguous United States was comprised of both wet and dry extremes which resulted in a near normal average for the period.

For the contiguous U.S. every month, with the exceptions of October and November, was near to above average in 2008. The increased precipitation during 2008 helped ease some of the drought stricken areas across the U.S. According to the U.S. Drought Monitor, the percent area of severe to extreme drought decreased by approximately 25% in the West. The severe to extreme conditions in the Southeast decreased by more than 50%. The average annual precipitation for 2008 was 30.48 inches (774 mm), which is 1.34 inches (34 mm) above the 20th century (1901-2000) average.

Seasonal Analysis:

Nationally, this was the 18th wettest winter (December-February) in the 1895-2008 record. The state of New York recorded its wettest winter on record, and the states of Colorado, Connecticut, Pennsylvania, and Vermont experienced their second wettest winter on record. The South region received below normal levels of precipitation, mostly due to a dry winter in Texas.

California had their driest spring (March-May) on record, while Nevada and Utah had their 10th and 11th driest springs on record, respectively. Conversely, parts of the central Mississippi valley received much above normal precipitation during the spring. Missouri experienced the fourth wettest spring, Arkansas the sixth, Indiana and Iowa the eighth wettest, and Illinois the tenth wettest spring in the 1895-2008 record.

Both Florida and New Hampshire experienced their wettest summer (June-August) on record in 2008. The Northeast as a whole experienced their ninth wettest summer on record as Maine, Vermont, New York, Massachusetts, and Connecticut were much above normal. Iowa had their seventh wettest summer on record. Below normal precipitation was confined to areas in the West and East. Tennessee, New Jersey, Delaware, and California all experienced a below normal summer which ranked in the bottom 25.

This was the 53rd driest fall (September-November) in the 1895-2008 record nationally. An average of 6.7 inches (169.1 mm) of precipitation fell across the contiguous U.S., which is 0.1 inch (1.2 cm) below average. Nebraska experienced its third wettest fall on record and the state of Kentucky experienced its 11th driest fall on record. On the regional level, the West North Central received much above normal precipitation, while the Southwest and East North Central regions received below normal precipitation.

The percent area of the contiguous United States very wet and very dry during each of the last 48 months is listed in the adjacent figure. These percentages are computed based on the climate division data set. Those divisions having the monthly total precipitation in the top ten percent are very wet and those in the bottom ten percent are very dry. In 2008, a tenth or more of the country was very dry during March, April, and September.

During February-September of 2008, a tenth or more of the country was very wet. The highest monthly percentage seen during 2008 was in August when 19% of the U.S. was very wet.

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Severe Storms

According to NOAA's Storm Prediction Center, preliminary estimates indicate that there were 2,192 reported tornadoes from January-December 2008, which is well above the ten-year average of 1,270. Of these tornadoes, 36 were rated EF3-EF5, which is equivalent to the average number of strong to violent tornadoes which have been reported over the period 1950-2008. Note that these numbers represent preliminary tornado reports and not the final number of total tornadoes.

The beginning of 2008 was an active severe weather period. There were 54 confirmed reports of tornadoes and five deaths across the Midwest between January 7th and 8th, making it the second largest January tornado outbreak on record. On February 5th, while 24 states held primary elections, 87 tornadoes occurred. This deadly event, nicknamed the "Super Tuesday Outbreak", caused 57 deaths in the southeastern U.S. for a total of 58 nationally in the month of February. The number of tornado related fatalities reported in February was the second highest on record for the month.

May was also an active month with 460 confirmed tornadoes, making it the third most active May on record. For the period January through May, a total of 112 tornado fatalities were reported. This year shares the record with 1968 as the eighth deadliest January through May period since reliable records began in 1953. Severe weather continued into June when two outbreaks spawned 289 confirmed tornadoes.

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Atlantic Hurricanes

The 2008 Atlantic basin hurricane season was above the 1950-2000 average with 16 named storms, of which eight were hurricanes, including five major hurricanes. The ACE index of hurricane activity indicated an above-average season, with a preliminary value of approximately 142 x104 knots2. In terms of accumulated cyclone energy (based on integrated wind power of all tropical cyclones during the season, both landfalling and those remaining out at sea), 2008 ranked as the 16th most energetic season out of the last 59.

The first 2008 Atlantic storm to make landfall in the U.S. was Hurricane Dolly. The storm made landfall in South Padre Island, Texas on July 23rd. While there were no direct deaths from the hurricane, it caused an estimated $1.2 billion of damage. Tropical Storm Fay was the first storm in recorded history to make landfall four times in a single state. Fay first made landfall in southern Florida on August 18th and continued to batter Florida through the 21st. Thirty-six deaths were blamed on the tropical storm and damages are estimated to exceed $180 million.

On August 25th, Hurricane Gustav formed in the South Caribbean as the season's second major hurricane. Hurricane Bertha on July 3rd was the season's first. Hurricane Gustav first made landfall in Haiti and again in western Cuba. On September 1st, Gustav made U.S. landfall in Louisiana as a category 2 hurricane. Gustav was blamed for a total of 138 deaths in the U.S. and the Caribbean and resulted in an estimated $4.3 billion of damage in the U.S.

As Gustav made landfall, Hurricane Ike began to form in the eastern Atlantic. Facilitated by favorable atmospheric conditions, Ike was able to quickly intensify into a category 4 hurricane on September 4th. On the 7th, while trying to recover from three earlier storms (Fay, Gustav, and Hanna), Cuba was hit again with winds estimated at 127-132 mph (203-213 km/h or 110-115 knots). Ike made U.S. landfall at Galveston, Texas, on September 13th as a category 2 hurricane. One-hundred-sixty-four deaths were blamed on Ike and damage estimates totaled more than $30 billion in the U.S., Cuba, and Bahamas, making Ike the third costliest hurricane of all time behind Andrew and Katrina.

Hurricane Paloma was the last major hurricane in the 2008 Atlantic Basin season. It was also the third major hurricane to hit Cuba (Gustav and Ike). This marks the first time on record that Cuba was struck by three major hurricanes in one season. Paloma made landfall in Santa Cruz del Sur, Cuba on November 8th and caused an estimated $1.4 billion of damage.

This year was the only year on record in which a major hurricane existed in every month from July through November in the North Atlantic (Bertha, Gustav, Ike, Omar, and Paloma). On July 20th, there were three active storms: Hurricane Bertha, and Tropical Storms Cristobal and Dolly. This was the earliest known date for three storms to be active on the same day. It is also noteworthy that none of the five major hurricanes (category 3 and above) were of major status at the time of U.S. landfall. This information is based on preliminary data and is subject to change. More details about these and all the 2008 Atlantic tropical systems can be found on NCDC's Atlantic hurricane page.

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Snow Season

The 2007-2008 snow season began with above average snowfall across parts of the Southwest and well-below-normal amounts in the Sierra Nevada, Cascades, and the Bear (ID, UT) and Salt River Ranges. A major ice storm struck parts of the south-central U.S. in the second week of December 2007, leaving over 600,000 residents in Oklahoma without power and causing over 20 fatalities across five states, prompting the governor to declare the ice storm the worst in Oklahoma history.

The same system later brought heavy amounts of snow to the Northeast, slamming Boston with up to ten inches (25.4 cm) on December 13th. As many residents began to clear out from the last storm, another strong upper-level system moved across the central U.S. through New England between December 15th-17th, bringing ice, sleet, damaging winds, and as much as 18 inches (45.7 cm) of snow in some areas. Detroit, MI, received 9.0 inches (22.9 cm) of snow, tying it as the 9th biggest December snowstorm on record. By the 17th, the total snowfall (19.6 inches/49.8 cm) in Boston, MA was more than the total snowfall of 2006-2007 (17.1 inches/43.4 cm).

February brought a series of large winter storms across much of the northern two-thirds of the U.S. By the end of the month, Boston's Logan International Airport broke a new February record for total precipitation, and parts of Wisconsin also set new seasonal snowfall records. In March, several additional cities broke seasonal snowfall records. Madison, WI set a new record for seasonal snow total of 100.1 inches (254.2 cm) on March 24, breaking the previous record of 76.1 inches (193.3 cm) from the 1978-79 season. Milwaukee, WI had its second snowiest winter on record as of March 24th. The seasonal snowfall total in Caribou, ME on March 21nd reached a new all-time record when the 2007-2008 total of 184.5 inches (468.6 cm) surpassed the previous record of 181.1 inches (460.0 cm) set during the 1954-55 snowfall season. By the end of the month, the snowfall total at Caribou was 190.7 inches (484.4 cm). Snowfall records at Caribou began in 1939. By the end of March, the winter of 2007-2008 in Concord, NH ranked as the second snowiest on record, only six inches (15 cm) shy of the all-time seasonal record of 122 inches (310 cm) set in the winter of 1873-74.

During the winter of 2007/2008, the snowpack levels were above-average in much of the Rockies, Cascades, and Sierra Nevada in the western U.S. At times, some areas in Oregon, Washington, Arizona, New Mexico, Nevada and southern Colorado had levels above 180% of normal. Conversely, parts of Wyoming, Montana, Nevada and north-central Washington had levels below normal, as did much of eastern Alaska and southern New Mexico. Above-average snowfall during the 2007-2008 season brought relief to many areas of the western U.S. that were plagued by drought in previous years.

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NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800.

NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts.

Citing This Report

NOAA National Centers for Environmental Information, Monthly National Climate Report for Annual 2008, published online January 2009, retrieved on September 22, 2023 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/national/200813.