Weather Extremes

The Remarkable Summer of 2010

By: weatherhistorian, 06:16 PM GMT die 22o September, anno 2010

The summer of 2010 will be remembered by millions of people around the world as the hottest in memory. In fact, it is probable that no warmer summer in the Northern Hemisphere has ever been experienced by so many people in world history; NOAA's National Climatic Data Center rated the summer of 2010 as the hottest in the Northern Hemisphere since record keeping began in 1880. From the densely populated I-95 corridor of the USA's mid-Atlantic region (New York City to Virginia), the entire region of western Russia (St. Petersburg to the Caspian region) and for almost all of Japan, there has never in modern records been such a warm meteorological (meaning June-August) summer.

Figure 1. Departure of surface temperature from average for the summer of 2010. Image credit: National Climatic Data Center (Data from China for August is not reflected in the map above since as of Sept. 15 final figures had not yet been received by the NCDC).

China and Japan
China recorded its warmest July and August since 1961, and June was the warmest on record for the northern third of the country. Beijing recorded temperatures of 106° on July 5 and 6, tying its all-time record for July. Some parts of the city reached 111° on those days. China also had its hottest temperature on record for an inhabited place, a reading of 48.7°C (119.7°F) at Tuyoq on June 20 (the record for an automated station is the 49.7°C that occurred on August 3, 2008 at Aydingkol.) Japan experienced its hottest summer since records began in 1898. August was Japan's single hottest month on record.

The almost unbelievable heat wave that affected western Russia was unprecedented for that region, and also was one of the deadliest heat waves in world history. The heat wave's death toll in Moscow alone was estimated by a city official to be approximately 11,000 in July and August. Russia's 2nd largest city, St. Petersburg, reached 98.8°F (37.1°C) on August 7--the hottest ever recorded there, and 7°F hotter than its prior all-time heat record. Moscow recorded its hottest temperature since records began in 1878 (downtown observatory), with 102.2°F (39.0°C) on July 29. This surpassed the previous record (set in 1921) by 4°F, although the 98° old record from 1921 was exceeded on 4 days during July and August. The month of July was an amazing 15° above average in Moscow. Imagine if Washington D.C. experienced such an anomaly--its average July temperature is 77.5°F, so the average temperature in Washington in July would have been 92.5°F, about 9°F warmer than the record 83.1°F seen in 2010. Accordingly, twenty days in Washington, D.C. would have exceeded 100°F, with the hottest day a scorching 110°, 4°F higher than the previous all-time record. Of course, the continental climate of Moscow can not be compared to the more maritime climate of Washington DC so this comparison is not entirely valid but is, nevertheless, indicative of just how extreme the heat event in Russia really was.

Figure 2. Smoke from fires in Russia on August 4 covers an area over 3,000 km (1860 miles) across. If the smoke were in the United States, it would extend approximately from San Francisco to Chicago. Visibility in Moscow dropped to 20 meters (0.01 miles) on August 4, and health officials warned that everyone, including healthy people, needed to take preventative measures such as staying indoors or wearing a mask outdoors. Image credit: NASA.

U.S. cities setting record warmest summer (June - August) temperatures
In the U.S.A., the following cities recorded their hottest meteorological summer on record (the most remarkable being the figure for Central Park in New York City where records go back to 1869 at the same location):

New York City (Central Park): 77.8° (old record 77.3° summer of 1966)
Washington D.C. National Airport: 81.3° (old record 80.0° summer of 1943)
Dulles Airport, VA: 77.8° (old record 76.8° summer of 2007)
Richmond, VA: 81.3° (old record 80.0° summer of 1994)
Atlantic City, NJ: 77.5° (old record 75.8° summer of 2005)
Philadelphia, PA: 79.6° (old record 78.9° summer of 1995)
Trenton, NJ: 77.7° (old record 76.5° summer of 1898)
Wilmington, DE: 77.8° (old record 77.7° summer of 1900)
Baltimore, MD: 79.2° (old record 79.1° summer of 1943)
Norfolk, VA: 81.1° (old record 80.0° summer of 1994)
Tampa, FL: 84.5° (previous record 84.2° in 1998)
Lakeland, FL: 84.6° (previous record 84.4° in 1987)
St. Petersburg, FL: 85.6° (old record 84.6° in 1987)
Asheville, NC: 75.4° (old record 75.1° in 1952)
Greenville, SC: 81.0° (old record 80.2° in 1952)

A cold summer for Coastal California

Santa Barbara, CA was the only major U.S. city that had its coldest summer on record: 61.9° (old record 62.2° in 1955. Several other California cities were unusually cool. San Diego had its 3rd coolest summer, and the Los Angeles airport (LAX) had its 2nd coolest summer. Ironically, Los Angeles (downtown site at USC) recorded the highest temperature ever recorded at any official site in the city on Sept. 27 with a 113° reading, edging out the old record of 112° set on June 26, 1990. Jeff has more about this in his blog today (Sept. 28).

U.S. cities setting all-time record highs
Hartford, CT tied its all-time heat record with 102° on July 6 (tied with July 3, 1966).
Norfolk, VA tied its all-time heat record with 105° on July 25 (tied with Aug. 7, 1918) and an unofficial temperature of 109° was reported from Williamsburg that same day, tying the record for the state of Virginia (a reading of 110°F from Balcony Falls on July 15, 1954 has since been disallowed by the Virginia State Climate Office).

U.S. cities setting hottest single month on record marks in July 2010
July was the single hottest month on record at Atlantic City, NJ: 79.8° (old record 78.7° in July 1983), and tied for the single hottest month on record at the following locations:
Washington D.C.: Warmest single month on record tied: 83.1° (tying July 1943)
Baltimore, MD: Warmest single month on record tied: 81.5° (tying July 1995)
Trenton, NJ: Warmest single month on record tied: 80.5° (tying July 1955 and July 1898)

...and August 2010:
Houston, TX: Warmest single month on record: 87.7° (old record 87.5° in July 1980 and earlier date)
Port Arthur, TX: Warmest single month on record: 85.8° (old record 85.6° in August 1962)

National heat records set in 2010
The year 2010 now has the most national extreme heat records for a single year--seventeen. The year 2008 is in second place, with fifteen. Here are the new records set during the period May - August:

Myanmar (Burma) had its hottest temperature in its recorded history on May 14 when the mercury hit 47.2°C (117°F) in Myinmu. This is the hottest reliably measured temperature in Southeast Asia records.

Pakistan had its hottest temperature on record on May 26 when the mercury hit an astonishing 53.5°C (128.3°F) at the town of Mohenjo-Daro, according to the Pakistani Meteorological Department. While this temperature reading must be reviewed by the World Meteorological Organization (WMO) for authenticity, not only is the 128.3°F reading the hottest temperature ever recorded in Pakistan, it is the hottest reliably measured temperature ever recorded on the continent of Asia (the reading of 129°F attributed to Tirat Tsvi, Israel in 1942 is an error.)

Kuwait recorded its hottest temperature on record on June 15 in Abdaly, according to the Kuwait Met office. The mercury hit 52.6°C (126.7°F).

Iraq had its hottest day in history on June 14 when the mercury hit 52.0°C (125.6°F) in Basra.

Saudi Arabia had its hottest temperature on record on June 22 with a reading of 52.0°C (125.6°F) in Jeddah, the second largest city in Saudi Arabia. The record heat was accompanied by a sandstorm, which caused eight power plants to go offline, resulting in blackouts to several Saudi cities.

Chad had its hottest day on record on June 22 when the temperature reached 47.6°C (117.7°F) at Faya.

Sudan recorded its hottest temperature on record on June 22 when the mercury rose to 49.7°C (121.5°F) at Dongola.

Niger set its record for hottest day on record on June 23 when the temperature reached 48.2°C (118.8°F) at Bilma.

Russia had its hottest temperature on record on July 11 when the mercury rose to 44.0°C (111.2°F) in Yashkul, Kalmykia Republic, in the European portion of Russia near the Kazakhstan border.The Asian portion of Russia also recorded its hottest temperature in history this year, a 42.7°C (108.9°F) reading at Ust Kara, in the Chita Republic on June 27.

Qatar had its hottest temperature on record on July 14 when the mercury hit 50.4°C (122.7°F) at Doha Airport.

Finland had its hottest temperature ever measured on July 29 when the mercury hit 37.2°C (99°F) at Joensuu Airport, Liperi.

Cyprus recorded its hottest temperature on record on August 1 when the mercury hit 46.6°C (115.9°F) at Lefconica.

Belarus recorded its hottest temperature on record on August 6 when the mercury hit 38.9°C (102.0°F) in Gomel.

Ukraine recorded its hottest temperature on record when the mercury hit 42.0°C (107.6°F) at Luhansk on August 12.

All-time national heat records were missed by 1°C or less in many other nations this summer, including China, the Azores, Morocco, Estonia, and Latvia.

Extensive credit for researching these records goes to weather records researcher Maximiliano Herrera, who maintains a comprehensive set of extreme temperature records on his web site.

National cold records set in 2010
No nations set record for their coldest temperature in history in 2010. Jeff Masters erroneously reported in his blog earlier this year that Guinea had done so. Guinea actually had its coldest temperature in history last year, on January 9, 2009, when the mercury hit 1.4°C (34.5°F) at Mali-ville in the Labe region.

Figure 3. New national extreme heat records set in 2010. Image credit:

Some causes for the excessive heat during the summer of 2010
All in all it may be estimated that about 300 million people, some 5% of the planet's human population, experienced their hottest summer ever. If we take in to account the fact that the months of June through August are normally the warmest season for only areas north of the Tropic of Cancer (22° N) in the Northern Hemisphere (and excluding South and Southeast Asia whose warmest months are April and May), then the figure is closer to 20% of the world population that can expect their warmest season to be June through August.

The cause for this in the Eastern Hemisphere can be blamed on a stubborn, stagnant upper-air pattern that began in Southeast Asia in May, slowly worked its way westward across South Asia and Southwest Asia in July, and finally into Eastern Europe by August. This same pattern also contributed to the catastrophic floods in Pakistan and China. In North America, a similar pattern developed in June with an amplified ridge developing over the eastern portion of the USA in June and remaining in place through August, while a persistent trough of low pressure in the Gulf of Alaska refused to budge all summer (and, ironically) resulted in one of the coolest summers on record for portions of California.

The other culprit for the record heat can perhaps be attributed to the general trend towards warmer weather globally as a result of human-caused climate change. This year is on track to be the warmest since record keeping began in 1880, according to both NOAA and NASA.

As climatologist Bob Henson of the National Center for Atmospheric Research (Boulder, CO) remarked following the record Western European heat wave in August 2003 that killed over 35,000:

If you push the baseline up {of temperatures} without changing the standard deviation, you're bound to raise the ceiling of record.

Christopher C. Burt


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Weather Extremes

About weatherhistorian

Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.

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