Difference from average temperature across Lower 48 during the summer (June-August) (NOAA’s National Climatic Data Center)

August ranked 16th warmest on record, with an average temperature 1.6 degrees above the 20th century average. Taking August together with the much warmer than average June (2 degrees above average, 14th warmest on record) and the singularly scorching July (3.3 degrees average), the entire summer averaged 2.3 degrees above average, trailing only 2011 (by 0.2 degrees) and 1936 (by 0.1 degrees) in the hottest summer rankings.

“The summer heatwaves this year were not quite as intense as the heat in 2011, but they affected more people,” writes Climate Central’s Andrew Freedman. “According to NOAA, more than 80 million people — about 10 million more than 2011 — experienced 100°F temperatures this summer.”

Percent of average precipitation in Lower 48 states during summer (June-August) (NOAA’s National Climatic Data Center)

Drier-than-average conditions prevailed across much of the central United States, from the Rocky Mountains to the Ohio Valley. Nebraska’s summer precipitation was almost 6 inches below average, and Wyoming’s precipitation was more than 2 inches below average, marking the driest summer on record for both states. Missouri, Illinois, Iowa, South Dakota, Nebraska, and New Mexico had summer precipitation totals among their ten driest.

At the end of August, more than two-thirds of the U.S. was experiencing moderate to exceptional drought. The hot, dry conditions stoked an active wildfire season. In August, more than 3.6 million acres burned nationwide, nearly twice average in the 12-year period of record.

Temperatures compared to normal for each calendar year through August dating back to 1895. The curve for 2012 (red) is much above the other warmest years (orange). (View big) (NOAA’s National Climatic Data Center)

Warmest 12-month periods on record (1895 to present). The bars colored in red encompass 2012. (View big) (NOAA’s National Climatic Data Center)