July 2012 Hottest Month On Record For Contiguous United States

(Newsroom America) -- The average temperature for the contiguous U.S. during July was 3.3°F above the 20th century average at 77.6°F, marking the hottest month on record for the nation.

The previous warmest July for the nation was July 1936 when the average U.S. temperature was 77.4°F, according to data from National Oceanic and Atmospheric Administration (NOAA).

The warm July temperatures contributed to a record-warm first seven months of the year and the warmest 12-month period the nation has experienced since recordkeeping began in 1895.

Precipitation totals were mixed during July, with the contiguous U.S. as a whole being drier than average. The nationally averaged precipitation total of 2.57 inches was 0.19 inch below average.

Near-record dry conditions were present for the middle of the nation, with the drought footprint expanding to cover nearly 63 percent of the Lower 48, according the U.S. Drought Monitor.

Higher-than-average temperatures engulfed much of the contiguous U.S. during July, with the largest temperature departures from the 20th century average occurring across most of the Plains, the Midwest, and along the Eastern Seaboard.

Virginia had its warmest July on record, with a statewide temperature 4.0°F above average. In total, 32 states had July temperatures among its ten warmest, with seven states having their second warmest July on record.

Drier-than-average conditions continued across the Central Plains and Midwest during July. Nebraska, Iowa, Illinois, and Missouri had July precipitation totals ranking among their ten driest. Maine had its fifth driest July on record.

An active storm pattern in the Southwest contributed to California having its fifth wettest July on record and Nevada having its eighth wettest. Wetter-than-average conditions were also observed through the rest of the Southwest, along the western Gulf Coast, and through the Ohio Valley where West Virginia had its tenth wettest July.

The warm and dry conditions over a large portion of the country were associated with ideal wildfire conditions. Over 2 million acres were burned nationwide during July due to wildfires, nearly half a million acres above average, and the fourth most on record since 2000.

The May-July months, an important period for agriculture, was the second warmest and 12th driest such three-months for the Lower 48, contributing to rapid expansion of drought. The central regions of the country were hardest hit by the drought, where ten states had three-month precipitation totals among their ten driest, including Nebraska, Kansas, and Arkansas which were record dry.

According to the July 31, 2012, U.S. Drought Monitor (USDM), 62.9 percent of the contiguous U.S. was experiencing moderate to exceptional drought at the end of July. This is an increase of about 6.9 percent compared to the end of June. The maximum value of 63.9 percent reached on July 24 is a record in the 13-year history of the USDM.

The area of the country in the worst drought categories (extreme to exceptional drought) doubled from 10 percent last month to 22 percent this month. The extreme dryness and excessive heat devastated crops and livestock from the Great Plains to Midwest.

The Primary Corn and Soybean Agricultural Belt, hard hit by drought, experienced its eighth driest July, third driest June-July, and sixth driest April-July (growing season) in the 1895-2012 record.

According to the Palmer Drought Severity Index, whose record spans the 20th century, about 57 percent of the contiguous U.S. was experiencing moderate-to-extreme drought in July. The last drought this extensive was in December 1956 when about 58 percent of the nation was in moderate-to-extreme drought.

The January-July period was the warmest first seven months of any year on record for the contiguous United States. The national temperature of 56.4°F was 4.3°F above the long-term average. Most of the contiguous U.S. was record and near-record warm for the seven-month period, except the Pacific Northwest, which was near average.