It’s the wettest 365-day period in Washington since record-keeping began in 1871, Jason Elliott, a hydrologist at the National Weather Service office serving the region, confirmed. He said the excess rain increases the risk of flooding, but “on the plus side, everything’s really nice and green."
Recall that Washington had posted its wettest calendar year on record to end 2018, but this most recent 365-day stretch has an even higher rainfall tally. The 71.05 inches of rain over the last 365 days surpasses the 2018 calendar year total of 66.28 inches by almost five inches.
This amount of rain is more than any of the 10 rainiest cities in the U.S. receive in an average year, including New Orleans and Miami.
The record-wet 365-day stretch coincides with an abnormally rainy period for the entire Lower 48 states. Last week, the National Oceanic and Atmospheric Administration released data that showed the contiguous United States had logged its wettest 12 months on record between May 2018 and April 2019.
The Mid-Atlantic region has been one of the soggiest parts of the country over the past year. Some of the most extreme precipitation totals have focused just north of Washington in northern Maryland, especially along and just north of the Interstate 70 corridor.
Jeff Craven, a volunteer weather observer who monitors precipitation near Thurmont (part of the Community Collaborative Rain, Hail, and Snow Network), has logged 91.54 inches in the past 365 days, which is unofficially a Maryland state record.
“It’s uncanny how wet it’s been. It’s so wet it swamps everything. Stuff doesn’t grow,” said Craven, who works as a meteorologist at the National Weather Service. “It seems like for the past year or so any time we get precipitation, it just seems to overachieve. It is crazy."
Tom Atkins, another volunteer weather observer who tracks rainfall data, said Craven’s 91.54-inch reading in Thurmont tops the previous 365-day record for Maryland of 91.15 inches in Towson, set between mid-Julys in 1971 and 1972.
In the past 365 days, Atkins has measured 88.43 inches at his location in Catonsville, which set the Maryland calendar year record in 2018 with 84.56 inches.
2019 is off to a wetter start than 2018, most of it falling on the weekend
Counting the 1.84 inches of rain that have fallen since Friday, over 16.5 inches have accumulated in Washington this year, which is about three inches above normal.
2018, which became the wettest calendar year on record, had received only 12.26 inches of rain up to this point, a slightly below-normal amount. But from the second half of May onward, it turned exceptionally wet.
2019 so far ranks as the 35th-wettest year on record year-to-date. If it has felt wetter than that, it’s because rain has fallen disproportionately between Friday and the weekend. Of the 48 days with measurable rain in 2019 so far, 32 have occurred between Friday and Sunday.
After four straight days with rain (Friday through Monday), a drier weather is finally predicted for the Washington region starting Tuesday.