Persistent, scorching heat in the central and eastern regions of the United States shattered long-standing daily and monthly temperature records last month, making it the fourth warmest July on record nationally, according to scientists at the National Oceanic and Atmospheric Administration’s (NOAA) National Climatic Data Center. The heat exacerbated drought conditions, resulting in the largest “exceptional;” drought footprint in the 12-year history of the U.S. Drought Monitor.

  “Exceptional” is the most severe category of drought on the drought monitor scale. Drought conditions at several locations in the South region are not as long lived, but are as dry, or drier, than the historic droughts of the 1930s and 1950s.

 The average U.S. temperature in July was 77.0 degrees F, which is 2.7 degrees F above the long-term (1901-2000) average. Precipitation, averaged across the nation, was 2.46 inches. This was 0.32 inch below the long-term average, with large variability between regions. This monthly analysis, based on records dating back to 1895, is part of the suite of climate services NOAA provides.

 Oklahoma and Texas had their warmest months everon record, with average temperatures of 88.9 degrees F and 87.1 degrees F, respectively. Oklahoma's statewide average temperature was the warmest monthly statewide average temperature on record for any state during any month.

 Forty-one of the lower 48 states had above-normal, much-above-normal, or a record warmest July. Only seven of the lower 48 states — all west of the Rockies — experienced a July average temperature near or below the 20th century average.

 Dallas exceeded 100 degrees F on 30 of the 31 days in July. In Oklahoma City, July was the warmest single calendar month, with an average temperature of 89.2, beating the previous record of 88.7 degrees F set in August 1936. Washington, D.C.’s Reagan National Airport had its warmest single calendar month on record, with an average temperature of 84.5 degrees F, breaking the previous record of 83.1 degrees F set in July 2010 and July 1993.

 The July heat wave was characterized by unusually warm minimum temperatures, during nights and early mornings. This is typical of U.S. heat waves in the last decade, and consistent with increasing warm summer nighttime extremes observed across much of the country since the late 20th century.