July tops US heat records


In 118 years of U.S. weather records, last month stands as king.

While Walla Walla has been spared the misery, July for the nation was hotter than any month previously observed. The National Oceanic and Atmospheric Administration reported Wednesday that the July average temperature over the continental United States was 3.3 degrees warmer than the 20th-century average — and 0.2 degrees hotter than the previous record, set in July 1936.

Some of July’s hottest temperatures occurred in the Plains, the Midwest and the Eastern Seaboard. Virginia had its hottest July on record, a full 4 degrees above average.

In 32 of the 48 contiguous states, July ranked among the top 10 hottest. At least 35 cities or towns had their hottest day on record for any day of the year.

The heat was intimately linked to a drought that expanded to nearly 63 percent of the Lower 48 in July. In a vicious cycle, high temperatures accelerated evaporation, which dried up the land surface, allowing for even more heat.

The worst of the drought centered in the Midwest and Plains. Nebraska, Iowa, Illinois and Missouri had July precipitation totals ranking among their 10 driest. NOAA said the area of the country in extreme to exceptional drought doubled from 10 percent in June to 22 percent in July. The drought reached the most extensive levels since December 1956.

The hot and dry conditions also stoked wildfires, which consumed more than 2 million acres in July, a half a million acres above average and the fourth-most on record since 2000.

Not only was July unrivaled for the heat it spread across the Lower 48, but so, too, were the past 12 months. Nationally, the past four 12-month periods have each successively established new records for the warmest period of that length.

In the 12-month span from August 2011 to July 2012, every state except Washington observed warmer-than-average temperatures.


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