Most Read: Local

Posted at 11:58 AM ET, 11/14/2011

What is Washington, D.C.’s weather like in November? Breaking down norms and extremes


November 17, 2007 — Fall foliage and the Jefferson Memorial. By CWG photographer Kevin Ambrose. See image larger.
Come November in D.C., it’s harder to deny that the cold season’s grip is tightening. Days are short and getting shorter. Leaves are dwindling even in the latest areas to hit peak color. And temperatures are on a noticeable decline. By month’s end, the entire region has recorded its first freeze most years.

Additionally, the high-moisture content of the summer is further depleted and the monthly precipitation average heading into the winter month continues declining. But, as with most months, it’s seldom truly dry in November, and the normal tally for the month is just behind that of the more variable (wet-to-dry) October.

Keep reading for more in this eighth installment of a year-long series of posts detailing specific statistics on climate norms, extremes, and averages for the each month in Washington, D.C…

PRECIPITATION

November’s average* monthly precipitation is 3.17”, an increase of .14” from the previous (1971-2000) climatological norm. It is the only month of the D.C. cool season (defined as Nov.-Mar. in this series) which saw an increase in precipitation during the last 30-year cycle.


Monthly rainfall (in inches) in Washington, D.C. from 1871-2010. See sources for data.

The wettest November on record occurred way back in 1877 when 7.18” of rain fell. The most precipitation that has fallen in recent history was 6.70” during November of 1963. A total of seven years have seen monthly totals of 6” or greater. The first year of the current climate record normals, 1981, was D.C.’s driest on record when only 0.29” of rain fell.

The loss of high-octant water content in the air becomes further evident into November as the daily record rainfall falls below 3”, with the 2.95” recorded on the 8th in 1943 the mark to be bested. A total of 11 days in November have seen rainfall of 2” or more, compared to the peak warm season months of October (25), September (39), August (41), July (37), and June (28).

November is typically a transitional month and not particularly notable in the precipitation department. Because of that, D.C.’s heaviest daily totals this time of year are likely to come in association with strong early-winter storm systems over the Midwest that can pump in warm and moist air from the south, as occurred on the rainiest November day in 1943. Coastal systems enter the mix more frequently, though they are less common than during the winter months. That said, some snow can fall...


The top ten accumulation events in November at Washington, D.C. Numbers are in inches of snowfall.

There have been roughly 45 events which produced accumulating (.1”+) snow in D.C. during the month going back to 1888 when snowfall records begin, so it’s more or less 15-times as likely to snow and stick (even a little bit) in November compared to October. Accumulating snow has been recorded on 55 separate days, with the 11.5” that came on the Veterans Days (the 11th) of 1987 the most significant daily and event accumulation of the month. [Extra: See a video clip from Nov 1987]

All of the top 10 storms in November are 3” or greater, with five of the group happening since 1953. These statistics may give the impression that November snow is not super uncommon in Washington, and that is increasingly true as one gets further west and north of the city into elevated areas. But, when examining the most recent years — somewhat like April snow — it seems like November snow is becoming an endangered species.

It’s been 14 winter seasons, from 1997-98 through 2010-11, since accumulating snow fell in D.C. during November. The next longest snowless stretch occurred from 1940-41 through 1949-50, and another of the same length ran from 1918-19 to 1927-28.

TEMPERATURES


November temperature averages throughout recorded history (in degrees F) at Washington, D.C. See sources for data.

As the month wears on, it’s harder and harder to venture out without some layering. Daytime temperatures can still prove quite pleasant, particularly early in the month. But a creeping chill is the general pattern throughout. On the bright side, if you don’t like cooler temperatures, the average for the month — now 49.6 degrees — is up 0.9 degrees from the previous 30-year norm. This is tied for the second largest gain of all the months.

Still on the monthly level, the warmest it’s been in November is 54.8 degrees in 2001. And the month has been as cold as 40.2 degrees (about an average December nowadays) in 1880, though 1976 is the coldest year in the National Airport specific portion of the records when it was 43.0 degrees.

Tellingly, the average daily high falls from 63 degrees at the beginning of November to 52 degrees by months end, while the low starts at 45 degrees and works its way down to 37 degrees. Along that trajectory, National usually averages its first freeze by the final third of the month (behind most spots in the area sans similar locales at low elevation and near water).

Using 1981-2010 data as a guide, highs in the 50s and 60s dominate the month, 37% of the time and 32% of the time respectively. Highs in the 40s (17%) are actually a bit more likely than ones in the 70s (12%), while 30s and 80s each make up about 1% of days. On lows, 40s and 30s are the story of nearly 4/5ths of overnight readings at 39% each. 50s rank in with 15%, 20s with 6% and 60s with 1%.


Raw (non smoothed) odds of a low temperature 32 degrees (freezing) or below at Washington, D.C., by day of the month. Both long-term and recent trends exhibit a similar pattern overall. See sources for data.

Though “lower D.C” often experiences its first freeze by late November, no night of the month stands better than even odds of seeing one. Raw odds (as seen above) do increase markedly through the month though. The suburbs, which have usually recorded a handful to a dozen or more freezes by late November, are more than likely nearing or passing the 50% mark for a freeze each night as December arrives.

As for expectional daily temperatures, there have been 21 days in total on record in the month with a high above 80 degrees. The highest November temperature on record occurred on the 1st in 1974 when National reached an 86 degree afternoon reading.

On the other end of the spectrum, 10 November days have seen highs below 30 degrees, though the most recent one was on the 30th in 1958. The coldest November day reached a high of just 24 degrees, occurring both in 1875 and 1929 on the 30th. Nine of the 10 occurrences were during 1930 or prior and the coldest “modern” daytime high of 31 degrees, also on the 30th, happened in 1976.

The 1st and 2nd of 1971 featured balmy 68 degree lows, a full 5 degrees above the warmest average high for the month, tying for the warmest November low on record. Compare that to November 30, 1930 when the low was 11 degrees! At National, the coldest temperature seen during the month was 16 degrees on the morning of the 29th in 1955.

DATA

30-year (1981-2010) Averages / Overall (all history) Averages...

Highs 60 or above: 13.3 / 11.4
Highs below 50: 5.5 / 8.1
Highs 70 or above: 3.7 / 3.2
Lows 50 or above: 4.9 / 3.6
Lows 40 or above: 16.6 / 13.1
Lows 32 or less: 3.9 / 7.0
Days with at least a trace of rain: 12.5 / 12.7
Days with .1” of rain or more: 5.3 / 5.2
Days with .5” of rain or more: 2.3 / 1.9
Days with 1” of rain or more: 0.9 / 0.6

Days with at least a trace of snow: 1.1 / 1.6
Days with 1” of snow or more: 0.1 / 0.2

Days with thunder: 0.7 / NA
Days with hail: 0.1 / NA
-This count is done through records on Weather Underground, and does not include the entire historical period.

All-Time Records (High / Low)...

Highs 60 or above: 23 (2001) / 2 (1910)
Highs below 50: 22 (1910) / 0 (2001, 2009)
Highs 70 or above: 12 (1975) / 0 (25 years)
Lows 50 or above: 13 (1985) / 0 (18 years)
Lows 40 or above: 26 (1985) / 4 (1910, 1995)
Lows 32 or less: 18 / (1901) / 0 (9 years)
Days with at least a trace of rain: 24 (1948) / 5 (1879, 1908)
Days with .1” of rain or more: 11 (1889) / 1 (4 years)
Days with .5” of rain or more: 5 (8 years) / 0 (20 years)
Days with 1” of rain or more: 4 (1932) / 0 (78 years)

Days with at least a trace of snow: 5 (5 years) / 0 (32 years)
Days with 1” of snow or more: 2 (1898, 1989) / 0 (103 years)

Days with thunder: 3 (1988) / 0 (11 years)
-Same as above. (30-year high / low listed)

SOURCES

Daily climate records for Washington, D.C., 1871-present
- See selected and additional statistics compiled for this post (Excel)

D.C. climate norms 1981-2010

D.C. November daily norms and records

D.C. monthly temperatures

D.C. monthly precipitation

NWS Baltimore/Washington climate information

NOTES

*All averages, unless otherwise noted, refer to the 30-year period of 1981-2010. Unlike prior months, a full set of new climate norms is now available and will be used throughout. Past months will be edited to reflect the new norms.

ABOUT THIS SERIES

While numerous local climatology statistics including daily, monthly, and seasonal normals and records are available from National Weather Service Baltimore/Washington, there are myriad other pieces of information which help frame the story. Rather than attempt to recreate what is already available, this series of posts will act as a companion to most information presented there.

This is the eighth installment of a series of living documents. Through early 2012, each month will be broken down in a similar or evolving way. As input is taken from the community, some items may be added to or changed in older postings. These postings will be updated as necessary to reflect changes when needed. Other articles may also become part of this series.

Feel free to share thoughts or additional data you may be interested in seeing.

Learn more about each month:

-April weather in Washington, D.C.
-May weather in Washington, D.C.
-June weather in Washington, D.C.
-July weather in Washington, D.C.
-August weather in Washington, D.C.
-September weather in Washington, D.C.
-October weather in Washington, D.C.
-November weather in Washington, D.C. (viewing)

Article last updated: November 14, 2011.

By  |  11:58 AM ET, 11/14/2011

Categories:  Local Climate, History, Latest

 
Read what others are saying
     

    © 2011 The Washington Post Company