July has been a memorable weather month across the DC area. From a flash flood emergency and a 100 year flood to DC's longest and most extreme heat wave in 3 years -- we've had a lot crammed into 4 short weeks.
This crazy month of weather has had a lot of folks in the newsroom asking about how it compares to last year. Do the July 8th flash floods mean DC will experience back-to-back record wet years? What about this crazy heat? We decided to break down the numbers.
Rainfall -- 2018 vs. 2019
Last year was DC’s wettest on record with 66.28”, breaking the 1889 record of 61.33” by nearly 5”. 2018's rain wasn't just impressive by that sole number alone -- we had a record 24 days in the year with at least 1" of rain! A huge chunk of the rain we received in the year was all the back half of the year. January was among the top 5 driest for DC standards, but that was followed by 4 other months among the top 4 wettest.
By comparison, 2019 in DC has also averaged above-average to date with over 28" of precipitation. This isn't as high as in 2018 -- but it's still more than 5" ahead of the pace for average annual rainfall. In the month of July alone, we've picked up 6.48" of rain, which is over 70% higher than the monthly average of 3.73".
Similarities between the years: DC has had several very heavy rainfall events and both were wet years.
This doesn't necessarily mean DC will end up with another record rainfall year. We've only examined statistics and numbers -- we don't ultimately know what the fall and end of the year will bring.
Hot Days And Heat Waves -- 2018 vs. 2019
Looking at the summer months, it's been a much hotter start to the summer of 2019 than last year. We've had 32 90-degree days so far in comparison to 2018's 22 days through July 27th.
This month alone, DC has had 18 days at or above 90 degrees, including 12 of those in a single heat wave, which was DC's longest and most intense in three years. Even though as of the end of July, 2019 is off to a hotter start than last year, it doesn't mean we'll end up hotter than in 2018. We had 23 days at or above 90 degrees in August, September, and October of last year.