April 2018 Global Climate Report

April 2018 Selected Climate
Anomalies and Events Map

Introduction

Temperature anomalies and percentiles are shown on the gridded maps below. The anomaly map on the left is a product of a merged land surface temperature (Global Historical Climatology Network, GHCN) and sea surface temperature (ERSST.v4) anomaly analysis as described in Huang et al. (2016). Temperature anomalies for land and ocean are analyzed separately and then merged to form the global analysis. For more information, please visit NCEI's Global Surface Temperature Anomalies page. The percentile map on the right provides additional information by placing the temperature anomaly observed for a specific place and time period into historical perspective, showing how the most current month, season or year compares with the past.

Temperatures

In the atmosphere, 500-millibar height pressure anomalies correlate well with temperatures at the Earth's surface. The average position of the upper-level ridges of high pressure and troughs of low pressure—depicted by positive and negative 500-millibar height anomalies on the April 2018 map—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.

April

April 2018 Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

April 2018 Blended Land and Sea Surface
Temperature Percentiles

Much of the globe had warmer-than-average conditions during April 2018. The most notable warm temperature departures from average were observed across southern South America, central Europe, eastern Russia, and Australia where temperatures were +3.0°C (5.4°F) or higher. Record warmth was present across southern South America, central Europe, and scattered across all oceans and parts of Australia. The most notable cooler-than-average temperatures during April 2018 were present across much of Canada and the contiguous U.S., where temperatures were -3.0°C (-5.4°F) or cooler. Record cold temperatures were limited to parts of the Midwestern contiguous U.S. According to NCEI's Regional Analysis, four of six continents had an April temperature that ranked among the five warmest Aprils on record, with South America and Europe having their warmest April on record.

Averaged as a whole, the temperature across global land and ocean surfaces for April 2018 was 0.83°C (1.49°F) above the 20th century average of 13.7°C (56.7°F) and the third highest April temperature since records began in 1880. Only April 2016 (+1.08°C / +1.94°F) and 2017 (+0.89°C / +1.60°F) were warmer. Nine of the 10 warmest Aprils have occurred since 2005. April 2018 also marks the 42nd consecutive April and the 400th consecutive month with temperatures, at least nominally, above the 20th century average. The April global land and ocean surface temperature has increased 0.07°C (0.13°F) per decade since 1880; however, the rate is more than double since 1980.

The global land surface temperature was the ninth warmest April in the 139-year record at 1.31°C (2.36°F) above the 20th century average of 8.1°C (46.5°F). The global ocean surface temperature was 0.65°C (1.17°F) above the 20th century average of 16.0°C (60.9°F) and the fourth highest temperature on record, trailing behind 2016 (+0.79°C / +1.42°F), 2017 (+0.72°C / +1.30°F), and 2015 (+0.66°C / +1.19°F).

Select national information is highlighted below. Please note that different countries report anomalies with respect to different base periods. The information provided here is based directly upon these data:

• Winter-like temperatures affected much of North America during April 2018. This was the coldest April since 2013 for North America as a whole and tied with 1918 as the 15th coldest since continental records began in 1910. Several locations in the Ontario province (Sudbury, Earlton, Barrie, Hamilton, and Windsor) had their coldest April on record, with monthly temperatures 3.0°–6.0°C (5.4°–10.8°F) below average. According to Environment and Climate Change Canada, daily temperatures were 15.0°C (27°F) below normal. On April 5 minimum (nighttime) temperatures were in the -20s°C (-36s°F), setting new low minimum temperature records in several locations. The contiguous U.S. had its coldest April in 22 years and the 13th coldest since national records began in 1895. Ten states had a record or near-record cold April temperature on record.
• Warmer-than-average conditions engulfed much of Europe during April 2018. Several central European countries had a record or near-record warm April. Germany's national April 2018 temperature was 12.4°C (54.3°F) or 4.0°C (7.2°F) above average—the warmest April since national records began in 1881. This value surpassed the previous record set in 2009 by +0.6°C (+1.1°F). Poland also had a record warm April (+0.6°C / +1.1°F), exceeding the previous record set in 1800. Austria had its second highest temperature departure from average at +4.6°C (+8.3°F), falling behind 1800 by 1.1°C (2.0°F). Austria's national temperature records extend back to 1767. France had its third warmest April since national records began in 1900 at 2.7°C (4.9°F) above the 1981–2010 average. This value falls behind 2007 (+3.6°C / +6.5°F) and 2011 (+3.3°C / +5.9°F).
• A heat wave, characterized by its unprecedented intensity and duration, affected Europe from April 18–22. France's national mean temperature on April 21 was 19.2°C (66.6°F)—the hottest day on record for the month of April, surpassing the previous record of 18.9°C (66.0°F) set on 30 April 2005. The average maximum temperature for the nation during the five-day period was 26.2°C (79.2°F), which is 9.7°C (17.5°F) above average. This was the highest five-day period for April since 1960. Many locations set new high maximum (daytime) and minimum (nighttime) temperatures for the month.
• Several stations across Denmark observed the earliest summer day, defined as days with a maximum temperature > 25.0°C (77.0°F), in over 50 years on 19 April 2018. The most notable maximum temperature of 26.7°C (80.1°F) was recorded in Karup. This value was also warmer than any temperature observed during summer 2017. April 17, 1964 was the last time maximum temperatures were greater than 25.0°C (77.0°F).
• De Bilt, Netherlands had its second warmest April since records began in 1901 with an average temperature of 12.2°C (54.0°F) or 3.0°C (5.4°F) above the 1981–2010 average. This value trails behind 2007 and 2011 (13.1°C / 55.6°F). The maximum temperature of 29.6°C (85.3°F) observed on April 19 was the highest April maximum temperature ever recorded in the Netherlands. April 2018 had a total of 9 warm days (defined as maximum temperatures > 20.0°C [68.0°F]) and 3 summer days (maximum temperature > 25.0°C [77.0°F]) in comparison to its normal of 3 warm days, while summer days usually do not occur in De Bilt or anywhere else in the Netherlands so early in the year.
• The United Kingdom's national mean temperature for April 2018 was 8.4°C (47.1°F) or 1.0°C (1.8°F) above the 1981–2010 average. Maximum and minimum temperatures were also above average across the nation. England's average April minimum temperature of 5.9°C (42.6°F) was the second highest since records began in 1910, behind 2011.
• Sweden had very cold temperatures at the start of April, with several stations in Svealand and southern Norrland recording their lowest April temperatures in three decades. However, warmer-than-average conditions affected the region mid-month. By April 20, maximum temperatures were as high as 27.2°C (81.0°F) at Oskarshamn—the highest April temperature for the nation since 2000 (28.8°C / 83.8°F).
• New April mean temperature records were set across parts of Slovakia. Of note, the stations in Oravská Lesná, Poprad, and Medzilaborcia surpassed previous records that were set in 1934. The April 2018 mean temperature in Hurbanov was 16.2°C (61.2°F), which is 4.9°C (8.8°F) above average. Several locations also recorded a high number of summer days. Hurbanov had a total of 11 summer days, tying with April 2000 as the most summer days since the mid-20th century.
• April 2018 was also exceptionally warm across eastern and central Pakistan. A heat wave affected eastern and central Pakistan from mid- to late-April. April 30 was Pakistan's warmest April day on record as temperatures soared to 50.2°C (122.4°F) in Shaheed Benazirabad (Nawabshah), setting a new national April maximum temperature record. This value is 10.0°C (18.0°F) above the April average value of 40.2°C (104.4°F). The previous record of 49.2°C (120.6°F) was set on 22 April 2017. Several locations set new April maximum temperature records as temperatures exceeded more than 40.0°C (104.0°F).
• April 2018 was exceptionally warm across Australia, resulting in the second highest April mean temperature since national records began in 1910 at 2.38°C (4.28°F) above the 1961–1990 average. This value falls behind 2005 by 0.28°C (0.50°F). The nation's average maximum (daytime) and minimum (nighttime) April 2018 temperatures ranked as the highest (+3.17°C / +5.71°F) and fourth highest (+1.59°C / +2.86°F) on record, respectively. The April 2018 national mean temperature was the highest monthly temperature departure from average among all months (1,300) on record; the national maximum temperature ranked as the third highest temperature departure from average for any month on record. All regions, with the exception of Tasmania, had a top four warm April, with New South Wales and South Australia having their warmest April mean temperature on record. Summer-like temperatures engulfed much of the nation during the first half of the month, with many locations setting new record-high April records.
• Argentina's national April 2018 temperature was 2.6°C (4.7°F) above average and was the highest April temperature since national records began in 1961. This value surpassed the previous record set in 1970 by +0.6°C (+1.1°F). During the month, several locations set new April mean temperature records that were +3.0°C or higher. Of note, the city of Buenos Aires set new mean (21.5°C / 70.7°F) and minimum (18.5°C / 65.3°F) temperature records in April 2018, exceeding the previous records by +1.1°C (+2.0°F) and 2.0°C (3.6°F), respectively.

ENSO-neutral conditions were present across the tropical Pacific Ocean during April 2018. According to NOAA's Climate Prediction Center, ENSO-neutral conditions are favored through September–November 2018. This forecast focuses on the ocean surface temperatures between 5°N and 5°S latitude and 170°W to 120°W longitude, called the Niño 3.4 region.

February Global Land and Ocean plot

February Global Hemisphere plot

The most current data can be accessed via the Global Surface Temperature Anomalies page.

Year-to-date (January–April)

January–April 2018 Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

January–April 2018 Blended Land and Sea Surface
Temperature Percentiles

The first four months of the year where characterized by warmer-than-average conditions across much of the land and ocean surfaces. The most notable warm temperature departures from average were present across the Middle East and Far East Russia, where temperatures were +3.0°C (5.4°F) or higher. Some of these locations had record warm April temperatures. Other areas with record warmth were observed across New Zealand and its surrounding ocean, as well as parts of Australia, and scattered across parts of the western and southern Pacific Ocean, Africa, and the Atlantic Ocean. Near to cooler-than-average April temperatures were observed across much of North America, Scandinavia, western Russia, eastern tropical Indian Ocean, central and eastern tropical Pacific Ocean, and across parts of the Atlantic Ocean. No land or ocean areas had record cold January–April temperatures. According to NCEI's Regional Analysis, four of six continents had a January–April temperature that ranked among the eight warmest such period on record, with Oceania having its warmest on record.

The globally-averaged temperature across land and ocean surfaces for January–April 2018 was the fifth highest in the 139-year record at 0.76°C (1.37°F) above the 20th century average of 12.6°C (54.8°F). Four of the five warmest January–April global land and ocean surface temperatures have occurred since 2015. The January–April global land and ocean surface temperature has increased 0.07°C (0.13°F) per decade since 1880; however, the rate is more than double since 1980.

The year-to-date global land surface temperature was 1.23°C (2.21°F) above the 20th century average of 4.8°C (40.5°F) and was the sixth warmest such period since global records began in 1880. The average global ocean surface temperature for January–April 2018 was the fifth warmest on record at 0.59°C (1.06°F) above the 20th century average of 15.9°C (60.7°F).

January–February Global Land and Ocean plot

January–February Global Hemisphere plot

The most current data can be accessed via the Global Surface Temperature Anomalies page.

Precipitation

April

The maps below represent precipitation percent of normal (left, using a base period of 1961–90) and precipitation percentiles (right, using the period of record) based on the GHCN dataset of land surface stations. As is typical, precipitation anomalies varied significantly around the world. Precipitation during April 2018 was generally drier than normal across the central and western contiguous U.S., Paraguay, central Argentina, central and eastern Europe, Australia, western Africa and scattered across eastern Asia. Wetter-than-normal conditions were notable across the eastern contiguous U.S., Uruguay, northern Argentina, western and northern Europe, and central and southern parts of Asia.

April 2018 Land-Only Precipitation
Percent of Normal

April 2018 Land-Only Precipitation Percentiles

Select national information is highlighted below. (Please note that different countries report anomalies with respect to different base periods. The information provided here is based directly upon these data):

• Much of Ireland had wetter-than-average conditions during the month, with several locations receiving twice their monthly normal April precipitation. Of interest, the Valentia Observatory, Co Kerry had its wettest April since 1940. This location also had its highest April daily rainfall since 2003 when it received a total of 46.2 mm (1.8 inches) of precipitation on April 16.
• Wetter-than-average conditions engulfed much of Spain during April 2018, with a national precipitation total of 137% of normal. The most notable precipitation totals were observed in northeastern Spain, where precipitation was three times the monthly normal. Also of note, the Pamplona Airport had a total of 171 mm (6.7 inches) of precipitation for the month—the wettest April on record. This value surpassed the previous record of 165 mm (6.5 inches) set in 2012.
• Portugal had its 14th wettest April since 1931 at 118.5 mm (4.7 inches) or 150% of its monthly normal precipitation total.
• Several locations across New Zealand's South Island had near-record precipitation totals for April 2018. Of note, Dunedin (Musselburgh) had a total of 155 mm (6.1 inches), which is three times its April normal precipitation total and ranked as the fourth highest since records began in 1918 for this location. Balclutha had its second highest April precipitation total at 120 mm (4.7 inches) or 251% of normal.
• Drier-than-average conditions plagued Australia during April, with the nation having its driest April since 1997 and the eighth driest since national records began in 1900. Several locations in the states of Victoria and New South Wales had their driest April on record. Of note, the Gabo Island Lighthouse (Victoria) only received a total of 0.8 mm (0.03 inch) of precipitation during April 2018, which is 83.1 mm (3.27 inches) less than the April average and was the driest April in its 156-year record. This value exceeds the previous record of 4.9 mm (0.19 inch) set in 1910.

References

• Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849.
• Huang, B., V.F. Banzon, E. Freeman, J. Lawrimore, W. Liu, T.C. Peterson, T.M. Smith, P.W. Thorne, S.D. Woodruff, and H-M. Zhang, 2016: Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.v4). Part I: Upgrades and Intercomparisons. J. Climate, 28, 911-930.

Citing This Report

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