Last week featured the coldest air in decades, but just how cold was it compared to the coldest January months recorded in D.C.?
January is typically the coldest month of the year with a normal temperature around 36°F, which is about 3°F colder than the next coldest month of February. The D.C. area has seen some very cold Januaries, and this month seemed like it would begin to challenge some of the coldest on record with below average temperatures in 7 of the first 10 days of the month and some of the coldest temperatures recorded in 20 years.
With four days in a row now recording 50 degrees or warmer, an extremely cold January doesn't appear likely. Even with the chance of more colder than normal temperatures next week, it just won't be cold enough to even make the top 10 coldest Januaries in the D.C. area.
Above is a look at the top ten coldest January's in D.C. The coldest averages 23.7°F for the month! That is the mean temperature for the month, which is the average of all the high temperatures of the month plus the average of all the low temperatures for the month divided by two. I took a look at the top three coldest months as I wanted to know what each was like compared to what D.C. experienced last week.
Related Blog: 102nd anniversary of record cold in D.C.
As a reminder, the temperature dropped to 11°F, 6°F and 13°F last Monday, Tuesday and Wednesday, respectively. That was very cold compared to the past few years, but nothing compared to the coldest months.
January 1940 - 3rd coldest January on record in D.C.
1940 featured some extremely cold temperatures, with only three days at or above 40°F. One of those days reached 55°F, the highest temperature recorded for the month. That January recorded nineteen days with high temperatures below 32°F, and five days with single digit low temperatures. Twenty-two days featured low temperatures below 20°F. Even if it dropped below 20°F for the rest of the month this year, that would only add up to twenty-one days!
January 1893 - 2nd coldest on record
1893 was downright cold. Oddly enough it didn't feature as many days with high temperatures below 32°F (16) as 1940, and had more days with highs above 40°F than 1940, but it was the extreme cold that really mattered.
From Jan. 10-22, 1893, there were ten days with low temperatures below 10°F. Two of the ten were below zero, including -5°F on the 14th, and -6°F on the 18th. Six of those day time high temperatures only reached the teens. Compare that to our coldest day last week which hit 21°F at Reagan National. All six of those days with highs in the teens occurred within an 8 day period. That's cold!
January 1918 - Coldest on record
1918 was just plain consistently cold. Like 1940, nineteen days featured high temperatures at or below 32°F. You know it's going to be a bad month when low temperatures start off with 1°F on the 1st, 10°F on the 2nd, 4°F on the 3rd, and 2°F on the 4th. Sheesh!
The highest temperature for the month was only 50°F, and only three days recorded high temperatures above 40°F. The difference between 1918 and 1940 were the low temperatures. 1940 featured four days with low temperatures above 30°F, whereas 1918 recorded its highest low temperature for the month at 30°F.
If you think back to Tuesday morning, it hit 41°F, which is two degrees shy of the normal high temperature for the day. Yes, 2014 won't be close to any kind of record breaking cold.
(Side note: For the history of where weather observations were taken, please consult this document)
Below is a look at the official 1893 January monthly climate summary which was sent to me with help from the National Weather Service office in Sterling, VA. Thanks for your help!