Halloween in the Nation’s Capital

The end of October often features some of the nicest weather of the year in the Nation’s Capital.  DC’s average high/low temperatures on October 31 are 64°/46°, according to NOAA.  Despite a cooler than average second half of October, this year’s Halloween is likely to be a warmer than average day with high temperatures around 70°.

DC’s record high on October 31 is 85° in 1950, while the record low for the date is 26° and has occurred more than once, most recently in 1917.  Over the last 25 years, DC has had measurable rainfall on only two Halloweens in 2002 and 2009.  The warmest Halloween in recent times was in 2004 when the high/low temperatures were 79°/59°, respectively, at National Airport.  Meanwhile, DC’s chilliest Halloween over the last 25 years occurred in 2002 with high/low temperatures of 47°/38°.  That’s more characteristic of mid-December than late-October.

October 2018 has been a unique weather month in the DC Metro Area.  It got off to an exceptionally warm start with above average temperatures on the first 11 days.  Nine of the first 11 days of October featured high temperatures of 81°/+.  Since October 12, all but six days have featured at or below average high temperatures in Washington, D.C.  

When the weather pattern shifted earlier this month, the conversation about October 2018 becoming the warmest on record in the Nation’s Capital came to an end.  That said, this month will still finish with a warmer than average monthly temperature (combining daily high/low temperatures) since the first 11 days were so much warmer than average.  Meanwhile, four of the five October’s from 2013 – 2017 were at least 2.9° warmer than average.  It will be interesting to see where October 2018 finishes up.

In addition to the warm start to 2018 with six of the first nine months of the year being warmer than average, this has also been a very wet year in the Nation’s Capital.  For the first time since 2003, Washington, D.C. had at least six consecutive wetter than average months (April through September).  While the Nation’s Capital averages 3.40” of rain in October, this month will finish with less than that – making it the fourth consecutive drier than average October.  

Since Washington, D.C. has had 52.89” of rain so far this year, it already ranks among the Top Ten wettest years on record.  If merely average rainfall occurs in November and December, then 2018 will finish with 59.11” of rain making this the fourth wettest year on record.

Washington, D.C.’s Ten Wettest Years (Source: NOAA)

1.  61.33” (1889)

2.  60.83” (2003)

3.  60.09” (1878)

4.  58.17” (1886)

5.  57.54” (1948)

6.  54.49” (1937)

7.  52.95” (1891)

8.  52.92” (1906)

9.  52.59” (1877)

10.  52.03” (1942)