Is DC’s rainy summer unusual?

 

I-270 during record July rainfall in 2019 (Source: Susan Granzow)

July is the wettest month of the year in the nation’s capital according to NOAA, with a monthly rainfall average of 4.33” based on the 30-year period of 1991-2020. In recent years, July has been a particularly wet month. 

Since 2017, the nation’s capital has had 14 July days with at least an inch of rain, including four days with at least 3” of rain. July isn’t usually an active month in the tropical Atlantic so most of this rainfall occurred absent any direct influence from a tropical system.

The irony about this July is the rainy weather pattern that began across the DMV (D.C., Maryland and Virginia) in May has continued for more than two months. That followed an extended period of below average rainfall in the nation’s capital that led to widespread moderate to severe drought conditions.

May 2025 finished as D.C.’s ninth wettest with 15 days of measurable rainfall, including two days of over an inch of rain. June was also wetter than average with another two days more than an inch of rain was measured at National Airport. The wettest day so far this month was July 9 with 1.16”. The good news is the drought conditions no longer exist, but the frequent and sometimes heavy rainfall has led to flooding in parts of the DMV.

None of D.C.’s rainfall since May has produced any daily rainfall records. Despite the rainfall surplus of nearly 5” since May 1, the nation’s capital hasn’t had a day with at least 2” of rain in more than 18 months. That’s unlike recent July’s that have featured heavy, record-setting rainfall. Nevertheless, localized heavy rain can lead to dangerous flooding events such as what occurred in parts of Silver Spring and Takoma Park, Maryland on July 19.

D.C.’s 10 wettest July days (Source: NOAA)

1. 4.69” (July 9, 1970)
2. 4.35” (July 22, 1969)
3. 4.25” (July 30, 1878)
4. 4.12” (July 30, 1876)
5. 4.05” (July 9, 2022)
6. 4.00” (July 21, 2018)
7. 3.68” (July 5, 1908)
8. 3.44” (July 8, 2019)
9. 3.37” (July 13, 1922)
10. 3.31” (July 28, 2017)

D.C.’s 14 July days with 1”/+ of rain since 2017 (Source: NOAA)

1. 3.31” (July 28, 2017)
2. 4.00” (July 21, 2018)
3. 2.79” (July 17, 2018)
4. 3.44” (July 8, 2019)
5. 2.04” (July 7, 2020)
6. 1.89” (July 23, 2020)
7. 1.27” (July 1, 2021)
8. 1.15” (July 9, 2021)
9. 4.05” (July 9, 2022) à Second wettest July 9
10. 1.38” (July 16, 2022)
11. 1.33” (July 14, 2023)
12. 1.57” (July 22, 2024)
13. 1.28” (July 25, 2024)
14. 1.16” (July 9, 2025)