Has autumn arrived?

 

A late-August day at the Avenel Park in Potomac, Maryland

August 2025 has felt more like September and will finish as DC’s coolest in decades. It will also become the driest August on record in the nation’s capital.

Following such a hot and humid June and July, the September-like temperatures to start August were particularly refreshing. In fact, the nation’s capital didn’t experience its first 90-degree August day until August 12. A four-day heat wave occurred from August 14 – August 17. The hottest temperature this month in the nation’s capital was 96° on August 17. It hasn’t been warmer than average since then and this month will finish with 24 cooler than average days.

Not only was August 17 the last 90-degree day in the nation’s capital this month, but it could also end up being the last 90-degree day of the year. That would be the earliest, last 90-degree day of the year for Washingtonians since August 4, 2004. This August is well-positioned to finished as DC’s coolest August since 2004. The five 90-degree days this month will also be the lowest such total for August in the nation’s capital since there were only three back in 2014.

August will finish cooler than June for a second consecutive year in the nation’s capital. That’s an impressive distinction since August is typically the second hottest month of the year in the nation’s capital based on average temperature.  

This has also been an exceptionally dry month in the nation’s capital with only 0.2” of rain. That’s well-below DC’s August average of 3.25”. It will break DC’s longstanding previous record for driest August by a considerable margin. That’s a hard pivot from recent August’s, as four of the last five have been wetter than average in the nation’s capital. 

The primary reason this month has been cooler and drier than average, aside from the several 90-degree days mid-month, has been the position of the jet stream. Consequently, “abnormally dry” conditions have resurfaced for parts of the DMV (DC, Maryland and Virginia) in the most recent Drought Monitor Index. That’s despite the combined rainfall surplus of over 5” for May and June in the nation’s capital.

Driest August’s in Washington, D.C. (Source: NOAA)

1. 0.20” (2025)
2. 0.55” (1962)
3. 0.59” (1998)
4. 0.62” (1930)
5. 0.74” (1943)
6. 0.77” (1917)
7. 0.85” (1892)
8. 0.88” (1995)
9. 1.01” (1884)
10. 1.03” (2006)

Average: 3.25”

Coolest August’s in Washington, D.C. (Source; NOAA)

1. 70.0° (1927)
2. 71.8° (1903)
3. 71.9° (1875)
4. 72.1° (1883)
5. 72.3° (1904)
6. 72.4° (1907, 1889)
8. 72.6° (1946, 1902)
10. 72.7° (1874)

Average: 79.4°