wpostServer: http://css.washingtonpost.com/wpost

The Post Most: Local

Posted at 11:13 AM ET, 11/22/2011

Washington D.C.’s Thanksgiving weather history

The warmest, coldest, wettest, and snowiest Thanksgivings


Frequency of high temperatures recorded on Thanksgiving in Washington, D.C.

Thanksgiving in the nation’s capital is shaping up to be sunny and seasonably cool this year. But if you’re like me and usually celebrate Turkey Day in the D.C. metro area, you probably recall some years offering typical November weather and others that were nearly warm enough to consider moving the meal outside. At the other extreme, we’ve even had a bit of snow to accompany the turkey on a few rare occasions.

In the spirit of the upcoming holiday, let’s take a look at some of Washington, D.C.’s coldest, warmest, wettest, and snowiest Thanksgivings since climate records began in 1872, taking into account the variable dates* on which Thanksgiving has occurred throughout history.

TEMPERATURES

As we would expect for late November, D.C.’s average high temperature on Thanksgiving Day over the past 139 years is 51.6 degrees, with an average low of 35.5F and an overall average temperature of 43.6F. Since 1872, 92 years (or two-thirds of all Thanksgivings) have seen high temperatures in the 40s or 50s, compared with 25 years of highs in the 60s, 15 years with highs only in the 30s, and 7 years with highs in the warm 70s.


Washington, D.C.’s warmest ever Turkey Day occurred in 2007 when the temperature at Reagan National Airport (DCA) soared to 77 degrees on Nov. 22, a record for the date (yet the day after, a cold front brought the high down to only 47 degrees!). Similarly warm Thanksgivings occurred in 1979 (75F on Nov. 22) and in 1933 (75F on Nov. 30, which remains D.C.’s record high temperature for the date).

On the flip side, D.C.’s coldest Thanksgiving by high temperature was on Nov. 27, 1930, when it only reached 30 degrees (still a record for the date). This was D.C.’s only Thanksgiving with a high temperature below freezing. More recently, a blustery high temperature of 35 degrees was recorded on Thanksgiving 1989 (following snow the day before) and again in 1996 – both were the coldest Thanksgiving high temperatures recorded at National Airport.

As for low temperatures, the lowest the mercury has ever dipped on Thanksgiving was 19 degrees on Nov. 26, 1903, followed by the above mentioned Thanksgiving of 1930 (with 21 degrees for a low). The lowest recorded Thanksgiving temperature since records began at DCA in 1945 was 25 degrees in 2005. On the whole, D.C. has experienced a freeze on Thanksgiving on 59 of the last 139 years; yet as many people are well aware, downtown low temperatures are usually not representative of the greater metro area.

PRECIPITATION

Given the atmosphere’s low moisture content as we approach winter, it’s not surprising that only small to modest amounts of precipitation have fallen on Thanksgiving in our area. Since 1872, fifty-four Thanksgivings have had measurable precipitation, of which only ten recorded more than 0.5 inches. Only Thanksgiving 1971 saw over 1 inch of precipitation (1.15”), part of which fell as snow. The wettest Thanksgiving brought 0.96” of rain on Nov. 30, 1916, and more recently, Thanksgiving of 1985 recorded 0.67” of rain on Nov. 28.

With already low odds of a white Christmas, D.C. can’t expect much in the way of snow on Thanksgiving. Nonetheless, snow has fallen on Turkey Day as many as 17 times. If that sounds like a lot, 11 of these years saw only a trace of snow (including, to my surprise, Thanksgiving 2010). Accumulating snow, however, has only coincided with Thanksgiving on six years.

WHITE THANKSGIVINGS IN D.C.


D.C.’s whitest Thanksgiving was in 1989: 1.9” of snow fell at DCA on Thanksgiving Day, on top of 1.6” that fell the previous day, Nov. 22. In second place, an inch of snow fell on Thanksgiving 1971. Perhaps most noteworthy is the 0.5” of snow that fell on Thanksgiving in 1938: the following day (Nov. 25), an additional 6.5” fell, making the combined total 7.2” of snow the second-highest November snowfall on record.

ARE THANKSGIVINGS GETTING MILDER?

Data from the last 30 years indicate that D.C.’s average high temperature on Thanksgiving has inched up to 53.2 degrees, with an average low of 37.3F and an overall average of 45.3 degrees. On each count, this represents an increase of about 1.6 to 1.8 degrees Fahrenheit compared to the overall averages listed above.


*Reflects adjusted data to account for later occurring Thanksgiving prior to 1939.
At first glance, it might seem flawed to compare Thanksgiving temperatures from the 1981-2010 period to the historical average. Prior to 1939, Thanksgiving sometimes occurred as late as November 29 or 30, which would favor tilting the overall averages toward lower temperatures. Interestingly, however, when all outlier years are removed (i.e. the 21 years when Thanksgiving fell on dates other than the standard November 22-28 dates), the temperature averages remain identical to those in the complete 139-year record.

The implication is that even when we account for the later Thanksgiving dates in the past, Thanksgiving still appears to be trending slightly warmer, which is consistent with other temperature increases seen in D.C.’s new climate normals.

Fortunately, this year we can be thankful for a sunny Thanksgiving holiday with pleasant late fall temperatures right about where they should be.

THANKSGIVING DATA RECAP

All Thanksgivings (1872-2010) / Thanksgivings in 1981-2010 Climate Period

Average temperature: 43.6 / 45.3

Average high: 51.6 / 53.2

Average low: 35.5 / 37.3

Warmest

Average temperature: 65 (1941) / 60.5 (2007)
High temperature: 77 (2007) / 77 (2007)
Low temperature: 56 (1934) / 54 (1992)

Coldest

Average temperature: 25.5 (1930) / 30.5 (1996)
High temperature: 30 (1930) / 35 (1989, 1996)
Low temperature: 19 (1903) / 25 (2005)

Most Precipitation

Rainiest: 1.15” mixed with snow (1971), otherwise 0.96” (1916) / 0.67” (1983, 1985)
Snowiest: 1.9” (1989) / 1.9” (1989)

Percentage of Thanksgivings with high temperatures in the…

30s: 11% (15 yrs) / 10% (3 yrs)
40s: 35% (49 yrs) / 30% (9 yrs)
50s: 31% (43 yrs) / 27% (8 yrs)
60s: 18% (25 yrs) / 27% (8 yrs)
70s: 5% (7 yrs) / 7% (2 yrs)

Percentage of Thanksgivings with lows…

At or below freezing (32ºF): 42% (59 yrs) / 37% (11 yrs)
Above freezing: 58% (80 yrs) / 63% (19 yrs)

Percentage of Thanksgivings with…

Precipitation: 53% (74 yrs) / 53% (16 yrs)
No precipitation: 47% (65 yrs) / 47% (14 yrs)

*Note that from the Civil War until 1939, Thanksgiving was observed on the final Thursday in November, allowing the holiday to occur as late as November 29 or 30. In 1939, however, President Franklin D. Roosevelt pushed for the holiday to be observed a week earlier than usual. In 1940 and 1941, Thanksgiving occurred as early as November 21 and 20, respectively, until the modern date of Thanksgiving was established in 1942 (the fourth Thursday in November, or anywhere from November 22-28).

Sources

November weather in Washington, D.C.
D.C. November climate norms and records

Capital Weather Gang’s Ian Livingston contributed to this report.

By  |  11:13 AM ET, 11/22/2011

Categories:  Latest, Local Climate, Holidays

 
Read what others are saying
     

    © 2011 The Washington Post Company