U.S. climate summary for August and summer 2021

September 10, 2021

Yesterday, NOAA’s National Center for Environmental Information released its U.S. climate summary for the month of August 2021 along with a recap of summer. According to the report, the average temperature for the Lower 48 states in August was 74.0 degrees Fahrenheit. That’s just under 2 degrees F warmer than the 20th-century average, which ranks as the 14th-warmest August on record.

Map of August 2021 temperature anomaly for the contiguous United States

Temperatures across the Lower 48 U.S. states in August 2021 compared to the 1981–2010 average. NOAA Climate.gov image from Data Snapshots, based on data from NCEI.

Meanwhile, the average U.S. precipitation for August was just over 3 inches, nearly a half inch wetter than the 20th-century average. Although some parts of the West enjoyed above-average rainfall—including the Northern Rockies states of Idaho, Montana, Wyoming, and Utah—the percent of the country in some level of drought increased marginally to 46.6 percent of the contiguous U.S.



(left) Total precipitation by U.S. climate division in August 2021 showing the dry-to-wet gradient across the country from West to East. (right) Percent of average precipitation in August 2021. NOAA Climate.gov images from Data Snapshots, based on data from NCEI.  large images: total precipitation | percent of average precipitation

According to NCEI, 2021 summer temperature (June–August) tied 1936 for the warmest summer on record, meaning this summer’s heat was equal to the extreme conditions the country experienced during the height of the Dust Bowl. Summers in the U.S. are growing warmer by 1.23 degrees F per century.

Graph of summer U.S. temperatures from 1895 to 2021

Summer (June–August) temperatures for the contiguous United States compared to the 20th-century average from 1895–2021. NOAA Climate.gov image, based on data from NCEI Climate at a Glance.

For more climate statistics for August, summer, and the year to date, see Assessing the U.S. climate in August 2021 at the NCEI website.