Abnormal cold to close November: possibly coldest in decades

November 22, 2013

First the good news: We’ve already experienced November temperatures colder than most of the last few years. Now the bad: There are several heavy doses ahead. Arctic blast number one this weekend, and another by turkey day.


Predicted temperatures for D.C. by last night’s run of the Global Forecast System through Thanksgiving. This is among the coldest of current guidance, but there is general support for two very strong early season cold shots. (Weatherbell.com)

With models unanimously predicting opportunities for highs in the 30s to finish out the month, I decided to take a look at how cold it needs to be before we think of it as atypical cold for November.

Related: What is Washington, D.C.’s weather like in November?

Let’s start with our most chilling November benchmarks, then discard them. Trivia night stuff, for sure.

D.C.’s chilliest high in the month is a silly-cold 24 degrees during another era of D.C. climate, occurring back in 1875 and 1929. The coldest November reading on record for Washington is an 11 degree low on the same day in 1929.


(Ian Livingston)

Narrowing to just the period in which D.C. weather has been recorded at Reagan National Airport, we find our coldest high to be 29 degrees (1958) and our coldest low to be 16 degrees (1955). Even pondering those extremes seems somewhat difficult in recent times.

Since climatology normals often use a 30-year averaging period, perhaps that gives us the best idea of how chilled we might expect to get in November.

When looking back at just the last 30 years ending 2012, the average coldest high of the month comes out to 43 degrees. The average coldest low? 29 degrees. Keep in mind, before our coming Arctic blasts, we’ve already seen a calendar day high of 45 degrees and a low of 30 degrees this month. Those are right around “normal” for our coldest November day.


(Ian Livingston)

Another metric besides cold highs and cold lows by year is how many days we end up spending in the 30s or lower in November. The short story there is that anything more than one is newsworthy across the last several decades.

The last November that D.C. recorded two days below 40 degrees was back in 2000. If you’re looking for a year with three or more in the 30s or below, we must dig back to 1956 when five occurred. Current indications are that we’ll not have too much trouble getting more than two. We’ll see from there!

Get ready to bundle up.

Cheat Sheet: “How long since it was so #@&% cold in November?”

Coldest monthly high

43+… 2009-2012
37… 2008
36… 2005
35… 1996
34 (or lower)… 1987 (33)
Below freezing… 1976
Coldest at National… 29 (1958)
Coldest in history… 24 (1875, 1929)

Coldest monthly low

31+… 2009-2012
26… 2008
25 (or lower)… 2005 (22)
21… 1986
20 (or lower)… 1976 (18)
Coldest at National… 16 (1955)
Coldest in history… 11 (1930)

Monthly days below 40

0… 2009-2012
1… 2008
2… 2000
3 or more… 1956* (5)
Most in history… 10 (1880)

*note: first publish had numbers transposed (1965 v 1956). 1956 is the correct year.

Ian Livingston is a forecaster/photographer and information lead for the Capital Weather Gang. By day, Ian is a defense and national security researcher at a D.C. think tank.
Comments
Show Comments
Most Read Local
Next Story
A. Camden Walker · November 22, 2013