By August, the peak of summer heat is usually behind us, but the month's swelter can still be unrelenting, especially during the first half. Occasionally, the first hints of the coming fall begin to appear.
Normal and record daily temperatures
August’s average temperature of 79.4 degrees is about 1.6 degrees cooler than July, the year’s warmest month. Average highs start around 88 degrees at the beginning of August and ease to about 86 degrees by the end.
The hottest temperature ever recorded in August is 106 degrees, reached Aug. 6, 1918. It is tied with July 20, 1930, for the hottest temperature ever observed in Washington. The coldest August temperature was 49 degrees, recorded Aug. 24, 1890.
Record daily precipitation
By August, thunderstorm activity typically begins to diminish, and the autumn jet stream has not yet strengthened, so the month is often quieter than June and July. Still, there have been some notable exceptions: four different August days have produced more than 5 inches of rain.
The largest total occurred Aug. 23, 1933, when 6.39 inches fell. August also marks the start of peak hurricane season, and the monthly rainfall record is tied to one of the most powerful hurricanes to affect the region — the Chesapeake-Potomac hurricane. The storm tracked just west of the Chesapeake Bay and Potomac River, sending a massive storm surge north into the region along with flooding rains.
Monthly temperatures by the year
The warmest August on record occurred in 1980, when the average temperature reached 82.8 degrees. The coolest came in 1927, when the monthly average was just 70 degrees — more than 4 degrees below normal at the time. As recently as 2025, August averaged a blissful 75.8 degrees, more than 3 degrees below the modern average.
Like other months in D.C., August temperatures have climbed over time. Around 1900, the average temperature for the month was about 75 degrees. Today, it averages close to 79 degrees.
Monthly precipitation by the year
The wettest August on record in Washington came in 1928, when 14.41 inches of rain fell. A large share of that total came from a tropical system that moved north from near Florida. The storm dumped 7.31 inches in 24 hours, including 5.97 inches on Aug. 11 alone. Hundreds of automobiles were reported stranded in floodwaters. Several other heavy rain events occurred during the month.
By contrast, the exceptionally pleasant August of 2025 produced just 0.20 inches of rain — the driest August on record. That’s roughly one-seventieth of what fell during the extremely wet August of 1928.
If anything, August precipitation appears to have trended slightly lower over time, although that could simply reflect natural variability.
Days at or above 90
The frequency of 90-degree days begins to decline in August, although the month still averages about 11 such days.
The most occurred in 2016, when temperatures reached 90 degrees or higher on 23 days. At the other extreme, several years have recorded only one 90-degree day during the month, most recently in the unusually pleasant summer of 2004.
August used to be known as hazy
August was once known not just for heat in the D.C. area, but also for hazy skies caused by poor air quality.
In the early 2000s, unhealthy air was fairly common. From 2000 to 2009, five Augusts averaged “code orange” air quality across the D.C.-area monitoring stations tracked by AirNow.gov, signifying unhealthy air for sensitive groups.
In recent years, conditions have improved considerably. About half of Augusts now pass without a single code orange day. In 2002 there were 22 days with code orange air quality or worse, but since 2017 five of nine Augusts have had none at all.
Today, August is the only summer month that averages “good” air quality in D.C.
Events of note
Aug. 1, 1983. A 150-mph wind gust was recorded at Joint Base Andrews, the strongest wind gust measured by an anemometer in the region at the time.
Aug. 6, 1918. Washington reached its all-time hottest temperature of 106 degrees for the first time during a nationwide heat wave.
Aug. 10, 1943. Six soldiers were killed by a lightning strike around 4 p.m. at Fort Belvoir, the region’s deadliest known lightning incident.
Aug. 11, 1928. Major flooding occurred as a tropical system passed nearby. A total of 7.31 inches of rain fell in Washington in 24 hours from Aug. 10–11.
Aug. 12, 1955. The remnants of Hurricane Connie swept through the region with more than 5 inches of rain and wind gusts near 60 mph.
Aug. 23, 1933. The Chesapeake-Potomac hurricane struck the D.C. area, producing an 11- to 12-foot storm surge on the Potomac River and a daily rainfall record of 6.39 inches.
Aug. 25, 1814. A tornado struck Washington as British troops were burning the city during the War of 1812. The storm is sometimes credited with helping hasten the end of their occupation.
Aug. 31, 1940. A plane flying from Washington to Pittsburgh crashed in a severe thunderstorm near Lovettsville, Virginia. Twenty-five people, including a U.S. senator, were killed.
