How Does this April Compare to Average ?

Great Falls National Park, Maryland

Despite the chilly start to April, this month is poised to finish as one of the warmest Aprils on record in the Nation’s Capital.  Some may recall that DC’s warmest April in nearly 150 years occurred just two years ago.  By comparison, last April was the first cooler than average one in Washington, D.C. since 2007.

Through April 23, DC’s average monthly temperature (combining daily high and low temperatures) is 61.5° (nearly 6° above average).  That’s largely the result of having 12 days with highs in the 70s since April 1.  Today is DC’s fourth day this month with highs in the 80s.  DC averaged only eight April days in the 70s and three to four days in the 80s for the period from 1993 – 2018.

Overnight low temperatures have been unusually warm over the first few weeks of April.  So far this month, there have been 12 days with low temperatures of at least 50° (including five days with lows in the 60s).  DC doesn’t average a low temperature of 50° until April 24, so having 12 such days through April 22 is somewhat unusual.  A new record high-low temperature of 63° was set in the Nation’s Capital on April 13.  That means the “low” temperature was 17° above the daily average of 46°.

This month has been drier than average, with only 1.62” of rain in the Nation’s Capital (0.62” below average through April 22).  Three of the last five Aprils were wetter than average in Washington, D.C., with the exceptions coming in 2016 and 2017.  Those two Aprils were part of an exceptionally dry 31-month period in the Nation’s Capital, from August 2015 through March 2018, when DC accrued a rainfall deficit of 16.42”.

However, this month hasn’t been unusually dry.  April 2019 won’t even crack the Top 10 for driest on record since DC’s tenth driest April occurred in 1976 with 1.17”.  The last 20 April’s have been evenly split by precipitation, with 12 of the last 20 being wetter than average.

Since warmer temperatures have the capacity to hold more water vapor than cold weather, it’s easier to see higher daily rainfall totals of 1”/+ during the warmer months of spring and summer.  That’s something Washingtonians saw a record number of last year (24) during DC’s wettest year on record.  

Warmest Aprils on Record in Washington, D.C. (Source: NOAA)

1.  63.8° (2017)
2.  62.1° (1981)
3.  62° (1994)
4.  61.6° (1985)
5.  61.2° (1960)
6.  60.9° (2010)
7.  60.6° (1941)
8.  60.1° (1980, 1977)
10.  60° (2002)