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December 2019

In a Rut: Temperatures Stuck in the 30s

30s

 

This post was inspired by the first four days of December 2019, all which reported highs and lows in the 30s.  The last time there was a streak of this length was in January 1998, when there was one of five days.  Although days "stuck in the 30s" aren't rare, as a typical year sees a half dozen of them, strings of three days or longer happen infrequently, about once very five years.  Not surprisingly, nine out of ten of these days have occurred from December thru March, with December having the most. (They've occurred as early as Oct. 26 and as late as April 11).

 

Chart - days in 30s by month

 

More than half of these days have reported measurable precipitation (57% to be exact); one in four have reported measurable snow.  Since many of these days have temperatures around freezing (two-thirds have a reading of 32° or colder for at least part of the day) the type of precipitation that falls is a mixed bag (i.e., rain, freezing rain, sleet and wet snow).  Often the type of snow that falls doesn't readily accumulate on paved surfaces if the temperature is above freezing.  And although temperatures in the 30s are far from frigid, the fact that they're often accompanied by overcast skies or precipitation makes these days feel raw and colder than the air temperature. 

 

Snow and rain

 

The most precipitation to fall on one of these "stuck" days was 2.03" on March 29, 1984 (high/low of 36°/34°); 1.8" of the precipitation was snow.  Additionally, there have been four other storms that produced two+ inches of liquid precipitation that crossed over to other days - in Jan. 1987, March 1967, Dec. 1930 and Dec. 1914 (all days were in the 30s).  The biggest of them all produced 3.49" of precipitation and lasted three days during the first week of March 1967; two inches of snow fell on the first day of the storm. 

 

Speaking of snow, the most to fall on a day with temperatures in the 30s for its entirety was ten inches on Feb. 10, 2010 (high/low was 34°/30°).  And 11.8" fell from a storm that crossed over into a second day on March 21-22, 1956.  In addition to these snowfalls there have been nine others that dropped six to ten inches (most recently on March 21, 2018 when 8.2" fell on a day in which the high/low was 39°/31°). 

 

Shoveling slust

 

In the years since 1900, the longest streak of days stuck in the 30s is five, which has happened three times: in Jan. 1998, Dec. 1970 and in Dec. 1914.  The most days in one winter was 20, which occurred in the winter of 1997-98.  Every winter except one, 1924, has had two or more days stuck in the 30s. (The winter of 1924 had one day.)  Finally, the most in one month is eight, which has happened twice - in January 1987 and January 1998.  (December 2019 had seven.)

 

Chart - stuck in the 30s

Chart - stuck in 30s by winter

 

If this analysis leaves you cold, I also posted one last year about days stuck in the 70s.

 

Stuck in a rut

 

 

 


November 2019 - Cold & Dry

The-month-november

 

November 2019 was the 31st coldest November and 32nd driest (going back to 1869).  It tied November 2012 as coldest November of this century.  Nine days had lows of 32° or colder, the most since 2013 and well above the 21st century average of three.  Looking at precipitation, the first 17 days of the month had just 0.25" of rain.  1.95" was measured for the entire month (more than two inches below average), with much of the rain concentrated during the seven days between 11/18-24.  Despite the cold temperatures no snow fell.  Other interesting aspects:

 

  • The 11-day period between 11/8-18 was ten degrees below average (six days had mean temperatures that were 10-20 degrees below average).  The month's other nineteen days had temperatures that were close to average, resulting in the month being 3.8 degrees colder than average overall (its average low was 4.5 degrees below average).  This was the most below average of any month since March 2015 (-4.4 degrees).
  • Half of the Novembers that were colder than Nov. 2019 occurred in the 19th century (1869-1899).  Looking at the past 100 years Nov. 2019 tied for ninth coldest.
  • The mildest reading of the month was 71° in the early hours of 11/1; the coldest reading was 23° on 11/13.  That reading was a record for the date and followed a record low of 25° the day before that. 
  • Since 1970 November's mildest reading has averaged 71°, which was the same as this November.  However, the second mildest reading has averaged 69°, but this year's was only 62°, which was the chilliest second mildest reading since November 1977.
  • Gusty winds on Thanksgiving Day somewhat marred Macy's Thanksgiving Day Parade.  Up until a few hours before the parade started it was uncertain whether its famous balloons would be permitted to float high above the streets of Midtown Manhattan, but it was decided to let them participate at a much lower height than usual.  Wind was the only issue as temperatures were at seasonable levels and there was no rain.

 

Low flying balloon at macys parade

 

  • On 11/13 the relative humidity at mid-day fell to an exceptionally low 13%, the lowest humidity reported in November in the years of the 21st century.  It was also the only date outside of March and April with a humidity level this low.
  • Last November, 3.3 degrees colder than average, seemed more wintry than this November because it featured a 6.4" snowstorm and had one of the coldest readings ever reported in November, 15°.  It also was one of the wettest Novembers.  While its average high was 0.9 degree colder than this November, it's average low was 1.9 degrees milder.  Like Nov. 2019, the equally cold Nov. 2012 was dry (1.81").  However, a big difference was that Nov. 2012 had a snowfall of 4.7" on 11/7-8 (the earliest accumulation of four inches or more).

 

Chart - 10 coldest novembers since 1960

Other November recaps:

2018

2017

2016

2015

 

 November in union square park nyc