Washington just witnessed its seventh wettest July on record. Drenching rain from several heavy storms catapulted the total into the top 10, concluding with the 3.88-inch deluge that fell Friday and Saturday.
Dulles had its wettest July on record with a 8.80 inches while Baltimore’s rain total ranked 19. Records in Washington and Baltimore date to 1872, while Dulles’s period of record is substantially shorter, going back to 1963.
How wet was July across the Washington DC and Baltimore MD region? pic.twitter.com/tkQXNaZYqI
— NWS DC/Baltimore (@NWS_BaltWash) August 1, 2017
In Washington, the monthly rainfall ended up an impressive 9.15 inches, the equivalent of an average three-month supply. It was easily wetter than any other July since the 1969, when 9.44 inches fell.
2017 is the only year since 2000 to feature a top-10 wettest July. All but two of the wettest Julys occurred before 1950:
Prior to July, Washington had a rainfall deficit for the 2017 calendar but the July soaking converted that to a surplus.
Temperatures were far more benign overall, with the monthly average temperature of 81.7 degrees, 1.7 degrees warmer than normal — very similar to July 2015. July 2017 ranks at about the fifth hottest of the 2000s and about 12th hottest since records began in 1872.
Year-to-date, 2017 now ranks as the second hottest of the 2000s:
Washington’s high temperatures spanned from 77 to 98 degrees during the month, but temperatures were much more frequently in the 90s than 70s. In fact, 20 of 31 days were 90 or higher, and we had seven days 95 or higher — frequently coupled with oppressive humidity. Our rainiest day on July 28, when 3.31 inches fell, was a record (see below).
Washington (9.15 inches of rain in July)
- July 13: Record-high minimum of 79 degrees tops 78 from 1993, 1992 and 1981.
- July 28: Record daily rainfall of 3.31 inches tops 2.9 from 1951.
Dulles (8.8 inches of rain in July)
- July 6: Record daily rainfall of 1.68 inches tops 0.64 from 1995.
- July 18: Record daily rainfall of 1.66 inches tops 0.92 from 1965.
Baltimore (7.11 inches of rain in July)
- July 6: Record daily rainfall of 1.54 inches tops 1.34 from 1931.
- July 28: Record daily rainfall of 2.58 inches tops 2.28 from 1871.
The July weather pattern
While the nation’s hottest weather in July definitely hit the West, we found a small patch of marginally hotter weather here in the Mid-Atlantic too. The main heat ridge resided in the West as shown in the second image below, and we experienced a little bit of jet stream weakness over the East, which offered us some back and forth weather instead of a sustained hot pattern.
July forecast review
Prior to July, we predicted the month’s average temperature and precipitation. How’d we do?
The temperature forecast
We said: “Look for temperatures to average from near to slightly above normal (0.5 to 2.5 degrees above normal) or about 80.3 to 82.3 degrees.” Reality: The average temperature was 81.7 — right in the range we predicted!
The rain forecast: We said “Near normal precipitation is favored (3.5 to 4.0 inches), but confidence is very low on that one.” Reality: 9.15 inches of rain fell — so we were quite a way off.
We nailed the correct temperature range, but precipitation is always more difficult and we indicated that.
Forecast grade: B-
What do you think? Tell us in the comments.
(Jason Samenow contributed to this post.)