2013-2014 winter: Arctic attacks from start to finish across the D.C. region (season statistics)

January 25, 2014 - An ice-covered Potomac River at dusk. (Ian Livingston)

January 25, 2014 – An ice-covered Potomac River at dusk. (Ian Livingston)

As outlined in our recap of meteorological winter (Dec-Feb), the region had a colder than normal run. Yet as cold as it seemed, it wasn’t even the coldest of the 2000s. But average doesn’t necessarily tell the full story of this cold season – rather, it’s the extremes – which occurred early and often.

Recall that in January, I looked at how cold the polar vortex blasts stacked up. When it came to cold extremes, the month ranked among the coldest in decades even if the average temperature wasn’t remarkably cold.

The character of January’s chill resonated through the cold season. Despite not having that super cold average temperature, the frequency of truly frigid air  was unquestionably uncommon.

Key points

*Repeated deep Arctic cold blasts, starting in late November and persisting through March
*D.C. reached 6 degrees in January, the coldest temperature since 1996 in the city
*Two of the ten coldest days since 1994 occurred in January in Washington, Jan 7 was the 25th coldest day at National Airport
*D.C.’s 17 lows in the teens or lower was the highest number since 1995-96
*Dulles recorded 13 lows in the single digits or lower ranked 5th most since opening in 1963
*Dulles’s 36 lows in the teens or lower was the most since 2000-01, and it logged its first subzero readings (2) since 1996
*All-time March low temperature records were set at Dulles (and Baltimore)

Related: The long, white 2013-2014 winter: Bringing snowy back to the D.C. region

Arctic outbreaks spread across five months

Daily temperature average (low + high / 2) at National Airport from November 2013 through March 2014, compared to normal. (Ian Livingston using NWS/NCDC data)

Daily temperature average (low + high / 2) at National Airport from November 2013 through March 2014, compared to normal. (Ian Livingston using NWS/NCDC data)

A number of significant Arctic outbreaks pummeled the region starting in late November (that cold snap made the top five weather events of 2013) and continued through March. Depending on how you count them, there were at least seven to eight significant cold snaps, some more like cold-snap sets – all mostly short in duration.

(There were also a number of quality warm-ups — perhaps less noticeable since we’ve seen some warm winters recently.)

Despite the big cold shots, D.C.’s winter average temperature didn’t even fall in the top half of the coldest on record. Given that, let’s focus on the coldest of the cold shots to differentiate the extremes from the “ho hum” average temperatures.

Though transient, the cold was “legit” – January

The coldest highs and coldest lows by year in D.C. as recorded at DCA. (Ian Livingston)

The coldest highs and coldest lows by year in D.C. as recorded at DCA. (Ian Livingston)

The low of 6 degrees on January 7 was the coldest D.C. has recorded since reaching 5 degrees on February 5 in 1996. The coldest high temperature of 19 degrees on January 22 was the coldest high temperature since 18 in January 2009.

Related:  January 2014: the coldest in decades in D.C. by many counts

January featured two of the top-10 coldest days the city has seen since the mega- cold of 1994 (which included subzero temperatures and one of D.C.’s coldest high temperatures back to at least the 1870s). January 7 slipped into the top-25 coldest days at Reagan National Airport since observations began there in 1945, at number 25.

Super cold nights piled up through the winter

Nights in the single digits or lower and the teens or lower at National. (Ian Livingston)

Nights in the single digits or lower and the teens or lower at National. (Ian Livingston)

I’ve focused just on period in which temperatures have been recorded at National Airport as they were recorded downtown prior to that. While the period back to 1871 is considered the same record, the cold was undoubtedly more common then for multiple reasons.

This cold season, D.C. recorded two lows in the single digits or lower (both in the single digits), and 17 lows in the teens or lower (including the two lows in the single digits). On both counts, these numbers were higher than anything we’ve seen since 1995-1996 when D.C. picked up two lows in the single digits or lower and 19 in the teens or lower. To find a winter with more super-cold mornings, we need to go back to 1993-94 when we saw six days with single digit or lower lows.

In the period National has been the observation spot, the largest tabulation of lows in the teens or less is 32 in 1976-77 and the largest total of lows in the single digits or less is six. For further perspective, the 30-winter average ending last winter is 8.7 mornings in the teens or lower and 0.8 in the single digits or less. We were well above average this winter on both of those counts.

It was much colder in our western suburbs

At Dulles and across western parts of the area, the low temperatures were truly punishing through January.   Then, a stealth blast of cold air arrived in March following the first of several snow events .

In January alone, Dulles recorded 16 days with lows in the teens or lower, 10 of those were lows in the single digits (exceeded by only two months on record: Jan 1977 with 13, and Jan 1970 with 12). The first subzero day since February 6, 1996 came along on January 23 when the mercury plunged to -2 degrees.

Nights in the single digits or lower and the teens or lower at Dulles. (Ian Livingston)

Nights in the single digits or lower and the teens or lower at Dulles. (Ian Livingston)

Related: Dulles Airport drops to -2, coldest temperature since 1996

The number of lows in the teens or below at Dulles — 36 through the end of March– is the highest since the winter of 2000-01, and well above the normal of 24 based on the prior 30 winters.

Examining the 13 lows in the single digits or lower at Dulles – tied for 5th most since records began in 1963-64- we have to go back to 1989-90 to find more (14).

The early March cold snap brought three of the 13 lows in the single digits or less Dulles recorded this season, including the second below zero low (of the cold season) when the mercury hit -1 on the 4th. That was the coldest temperature ever recorded at Dulles in March. (While two subzero temperatures and the March record is certainly amazing lately, below zero numbers used to be fairly common at Dulles before 1996.)

March is the new winter

The whole area finished well below normal when it comes to March. In our western and northern zones, it was most pronounced.

CFS re-analysis showing temperatures between 3C and 4C below normal for the month of March around the D.C. area. (Weatherbell.com)

CFS re-analysis showing temperatures between 3C and 4C below normal for the month of March around the D.C. area. (Weatherbell.com)

Overall, Dulles set four record low (minimums) in March (see below). Additionally, five record low high (maximum or daytime) temperatures were penned (see below). This includes the coldest high temperature so late in the year, when it hit only 33 on the 26th of March. Just the day prior that same mark was broken.

Related: Coldest, snowiest March on record at Dulles Airport, snowiest since 1960 in D.C.

In D.C., with an average temperature of 42.9 degrees, it was the coldest March since 1996 which recorded the same average. The most recent March colder than this year was occurred in 1993 (with an average temperature of 42.2 degrees).

Dulles finished with the coldest March on record (since 1963) at 37.4 degrees, besting the prior coldest 37.5 degrees in 1984. Brrrr.

Lots of records, except in D.C.

Ice in the developing stages on the Capitol Reflecting Pool during the evening of Jan. 3, 2014. (Ian Livingston)

Ice in the developing stages on the Capitol Reflecting Pool during the evening of Jan. 3, 2014. (Ian Livingston)

D.C. set only one record through the five-month (November to March) period when it came to cold temperatures. That happened when the high was 19 degrees on January 22. It was the lowest high temperature ever seen on that date.

However, Dulles, with the historical record less than half as long, added quite a few 2014 stamps to its coldest of days.

Record low maximums were set at Dulles on 10 occasions: Jan. 7 (18 degrees); Jan. 22 (15 degrees); Jan. 24 (21 degrees); Jan. 28 (18 degrees); Feb. 28 (28 degrees); Mar. 4 (29 degrees); Mar. 17 (30 degrees); Mar. 24 (39 degrees); Mar. 25 (33 degrees); Mar. 26 (33 degrees).

Six record lows were also set there, including the all-time March low on the 4th: Jan. 7 (1 degree); Feb. 28 (10 degrees); Mar. 3 (1 degree); Mar. 4 (-1 degree); Mar. 24 (19 degrees); Mar. 27 (15 degrees).

Further north at BWI, record low maxes were set on Jan. 7, Jan. 22, and Mar. 26. Record lows were reached on Jan. 7, Mar. 3, Mar. 4, and Mar. 27. (Unlike D.C. vs its previous location, BWI vs its former Baltimore location tends to run colder than the city, and D.C. was heavily impacted by urban heat island effects in the March cold waves in particular.)

Parting thoughts

March was a lion. (walter-in-fallschurch via Flickr)

March was a lion. (walter-in-fallschurch via Flickr)

Meteorological winter (December through February) 2013-14 was volatile and unmistakably cold, punctuated by short blasts of near-historic cold. March was a lion.

(Interestingly enough, cold high temperature counts (e.g., days below freezing) were not particularly noteworthy. For that reason I gave them little attention here. However, there were no doubt many days when high temperatures were well below normal).

After so much warmth in recent winters, this winter proved legitimate cold is not always a thing of the past.

Also on Capital Weather Gang

Animation of tsunami from northern Chile earthquake, Hawaii under advisory