Exploring December weather on Long Island

December is here, and that means short, colder days with an increased chance for snow! Digital meteorologist Geoff Bansen tells us what we should expect and looks back on some wild weather events.

News 12 Staff

Dec 3, 2019, 11:03 PM

Updated 1,655 days ago


December is upon us, and that means the holidays are right around the corner.
It also means that the days are short, the air is getting colder and our chances for snow are increasing!
While the amount of daylight will decrease up until the winter solstice on the 21st, the earliest sunset will have already occurred on the month's first day. In fact, the sun will actually set later on the shortest day of the year. How is this possible? It is because the sunrises will continue to get later all month long, and at a greater pace than the sunset change.
It all amounts to a measly 9 hours and 15 minutes of daylight. Compare that to the summer solstice, which gets approximately 15 hours!
December starts out with daily average highs/lows of 48 and 33 degrees, respectively. By New Year’s Eve, those numbers drop to 39 and 24.
Last NYE we got very lucky temperature-wise. While the morning low was 26 (right on par there), a high temperature of 47 was reached - not in the afternoon, but right as the ball began to drop at 11:59! Unfortunately, we were also in the midst of a soaking rain – an inch and a half fell between 9 p.m. and 3 a.m. New Year's Day.
Speaking of precipitation, December is the 4 wettest month, averaging 4.06”.  We’ve seen as much as 8.96 inches in 1996 and as little as 0.90 inches in 1985. And those inches don’t always falls as plain rain.
We typically see about 5.4” of snow during the month, but we've gotten as much as a whopping 25.3” in 2009! Snowstorms really don’t start becoming prevalent until December, and Long Island has gotten some doozies.
Let’s start with 2009. That year, about 95% of the month’s big snow total fell in one shot between December 19 and 20, from what became known as the blizzard of ‘09. The snow started Saturday afternoon and lasted into Sunday. Nassau saw 14-18", but Suffolk was the hardest hit with 18-27"! Islip MacArthur Airport picked up 23.9” and Brookhaven National Lab received 26.3“, making it the biggest single snowstorm for BNL at the time. Winds of 40 mph led to whiteout conditions and huge snow drifts. Temperatures dropped into the mid-20s. More than 1,200 flights were canceled and hundreds of LIRR passengers were stranded. There were dozens of car spin-outs, and many vehicles were abandoned. Even though folks had all day Sunday to clean up, most schools were still closed on Monday.
In 1947, Long Island had a White Christmas…. a day too late. The storm dropped 26.4" of snow in NYC, the most ever for one storm at the time. Here on Long Island, 19" fell at BNL, which began a record 55 straight days of snow cover! Snow remained on the ground until February 19.
63 years later, the blizzard of 2010 dumped 12-20" snow. Wind gusts over 65 mph led to 3-4 foot drifts. Besides the scores of accidents, all flights were canceled at every single metropolitan airport. Around 10,000 flights in total were canceled over the next five days in northeast.
But it’s not all about snow. On December 11 and 12 1992, one of the worst nor'easters in Long Island history battered the Island with 3" of rain, wind gusts to 90 mph and tides 8-15’ above normal, leading to severe coastal flooding and beach erosion. (Sounds eerily similar to Sandy, doesn’t it?)
Those same two days 16 years later, we saw a different kind of flooding. Long Island picked up 3.5" - 5" of rain in 24 hours! Some notable amounts include Medford (4.90") Central Islip (4.88") and Middle Island (4.85")
December 17, 1973 was a cold one. On top of subfreezing wind chills, an ice storm with accretion of 1” or more led to 125,000 outages. 245,000 commuters were stranded more than 10 hours on the LIRR, and there were countless accidents.
On the flip side, December 2015 was anything but cold. It was the warmest on record, with every single day’s max temperature reaching above average. This also included six straight days with record-high temperatures (the 10th – 15th) and the warmest Christmas (65°).
But that pales in comparison to a day in 1998. We hit the temperature jackpot, 77° on the 7th! That made it the warmest day ever recorded in the month. Break out the shorts!
December 12-13, 1964 became known as “A weekend that made aviation history”. A dense fog event dropped visibility to zero everywhere. All airports were closed.
Hey, was that Santa landing on the roof early? Nope. December 20, 1940 a magnitude 5.6 earthquake centered in New Hampshire sent tremors across LI during the middle of the night. A few days later on Christmas Eve morning, another magnitude 5.6 quake did the same during. Both events were especially felt in the Nassau along the North Shore. Fortunately, no damage was reported. 
How about the odds of a White Christmas? Well, they aren’t very good (< 25%) and there have only been a handful on Long Island (11 out of the 55 on record). But that doesn’t mean they can’t happen!
The official definition of a white Christmas is: "1 inch of snow on the ground on December 25". This means the snow does NOT have to fall on Christmas Day, which has only happened three times since 1963!
What about the other holidays?
First day of Hanukkah (this year on Dec. 22)
Normal high is 41°, with a record of 61° in 2013.
Normal low is 26°, with a record of 9° in 1989.
The most snow was 10” in 1975.
First day of Kwanzaa, Dec. 26
Normal high is 40°, with a record of 64° in 1982.
Normal low is 25°, with a record of 5° in 1983. (What a difference a year makes!)
The most snow was 11.3” in 2010.
New Year’s Eve Day, Dec. 31
Normal high is 39°, with a record of 59° in 1992.
Normal low is 24°, with a record of -1° in 1963. (Can you imagine the ball drop that year?)
The most snow was 2.3” in 1966.
Lastly, we couldn’t end this without a monthly moodcast! The emoji that best describes December weather is....
Yes, it's getting colder, but with the holidays coming, who isn't smiling?

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