Today in New York Weather History: December 17

 

 

Dec. 17 is the average date of the first high temperature of 32° or colder (based on the period 1970-2020).  It's happened as early as Nov. 22 (in 2008) and Nov. 23 (1989), and as late as Jan. 20 (1986).  In more than half of the years the first high of 32° or colder was 31° or 32°, but it's been as cold as 20° (which happened in the winter of 2007-08, when it occurred late, on Jan 3).   

 

1904 (Saturday)

A snowfall of six inches (three inches this evening, three inches tomorrow morning) came four days after a snowfall of seven inches.

 

1919 (Wednesday)

Four days after the temperature reached 61°,  tonight, shortly before midnight, the mercury dropped to one degree above zero.  This was the first of fifteen days this winter with lows in the single digits or colder.

 

 

1932 (Saturday)

Snow that began late in the morning continued through early morning on 12/18, amounting to 7.2".  Today's temperatures were also very cold, with a high/low of only 21°/10°.  (The snow was gone by Christmas Day, which had a high of 59°.)  The next measurable snowfall wouldn't be for another seven weeks (2/4).

 

1951 (Monday)

Today's frigid high/low of 20°/8° (22 degrees below average) would be the coldest day of the winter.  Skies were clear.

 

1971 (Friday)

This was the twelfth day in a row with above average temperatures.  During these dozen days temperatures were ten degrees above average.  Even after passage of a cold front early this morning, and temperatures falling throughout the day, the mean temperature was five degrees above the norm.  This stretch of mild weather followed a two-week period of colder than average weather. 

 

1973 (Monday)

The epic ice storm that began yesterday afternoon continued through this morning.  Conditions were worse than yesterday as sleet and freezing rain fell at an even heavier rate.  In total, 1.46" of precipitation fell - all in the form of sleet or freezing rain.  The temperature stayed below freezing all day, and by midnight had fallen to 17°. 

 

 

1996 (Tuesday)

Light showers through early afternoon amounted to 0.12".  This was the 146th day this year with measurable precipitation, establishing 1996 as the year with the most days of precipitation in the 20th century, passing 1972, the previous crown holder.  And there would be six additional days of precipitation before the year ended.  (The average number days of precipitation per year is 121.)

 

1998 (Thursday)

Today was the 25th day in a row with above-average temperatures.  During this stretch of mild days temperatures were ten degrees above normal.  (This would be the mildest December since 1984.)

 

 

 

2000 (Sunday)

Today's high of 62° was a record for the date, just one of five days with above-average temperatures during a December that was quite cold (5.5 degrees below average) - the coldest since 1989. 

 

2001 (Monday)

This was the 18th day in a row in which no low temperature was duplicated.  During these days (beginning on Nov. 30) they ranged between 32° and 58° - all above average.

 

2012 (Monday)

Only three degrees separated the day's high (43°) and low (40°) on a raw, "gloomy Gus" kind of day. 

 

2013 (Tuesday)

Light snow, occasionally mixed with sleet, fell throughout the daytime hours and amounted to 1.5".  This was the fourth snowfall of the past ten days, totaling 8.6".  Three of these snow "events" delivered one-inch+ - the most such snowfalls in December since 2005.  Besides being snowy, the ten days since 12/8 were also quite cold, with the average high/low of 35°/26° nearly eight degrees below the norm.  

 

 

2015 (Thursday)

It was a mild and rainy day.  The 1.25" of rain that was measured in Central Park fell mostly between 11 AM and 4 PM.  This was the eighth day in a row that had a mean temperature more than 10° degrees above average.  The average high/low during these days was 63°/52° - nineteen degrees above average.

 

2016 (Saturday)

Six days after the first measurable snow of the winter (0.4"), today saw the first snowfall of one inch or more as 2.8" accumulated between 4-8 AM.  Then it changed to sleet, then to freezing rain, all of which was over by noon.  (By contrast, last winter's first one-inch snowfall wasn't until 1/23 - the blizzard that buried the City under its biggest snowfall on record.)

 

 

2018 (Monday)

Light wraparound showers in the wee hours of the morning (amounting to just 0.03"), remnants from yesterday's rainstorm, made this the 152nd day this year with measurable precipitation, tying 1996 for the all-time record.  What distinguishes 2018 from 1996 is that its total precipitation for the year was more than five inches above 1996's (with two weeks remaining in 2018).

 

2021 (Friday)

Just three days after Central Park registered its lowest humidity level in December this century (20% later in the afternoon), today had an even lower humidity level - 14% (also during late afternoon).  As low as this was, it was twice as high as the 7%  humidity reported on 4/6 of this year.

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In a Rut: Temperatures Stuck in the 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 (including 2023), 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).

 

 

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. 

 

 

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°). 

 

 

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.)

 

 

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

 

 

 

 

November 2019 - Cold & Dry

 

 

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.

 

 

• 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).

 

Other November recaps:

2018

2017

2016

2015