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Photo taken earlier this month in St. Albans, Vermont is
not the look of a traditional January in the Green Mountain
State. No snow, fog, gloom, even hints of green grass.
Subzero cold is on the decline in Vermont. |
The weather pattern is finally changing.
We/ve managed to receive some decent, if definitely not colossal amounts of snow in the past week to ten days. It's also starting to turn a little colder, though so far it's not nearly like a winter hardy Vermonter has seen before.
If longer range forecasts pan out, we might even see some below zero weather for a change. Those subzero readings could come as early as this coming Wednesday or Thursday.
Such weather is a wintertime staple in Vermont, but not this year. Honestly, it's been a banana belt winter so far. In some ways, it's unprecedented. I've got the receipts to prove it.
WARM 2022-23 WINTER DATA
At Burlington, it still hasn't gotten to zero degrees or below yet. Subzero weather usually first hits in December, or maybe early January in the warmest winters.
Since at least 1917, probably earlier, Burlington has had a first zero of the season later than this year only four times. Well, three, to be entirely accurate. During the winter of 2001-02, it never got below zero, the only winter on record that has happened.
The coldest it has been in Burlington so far this winter is 8 above on December 24.
All of those four winters whose first zeros were later than our current toasty winter still had colder conditions by mid-January than this year.
Even in the continuously above zero winter of 2001-02, it had gotten as cold as 2 above in Burlington by the 19th of January. All of those other "late" subzero winters were colder than it's been so far this year.
Back to this winter: I've only counted 20 days that have failed to get above freezing this winter as of January 23. We've had at least one winter with 51 days of subfreezing days in a row, never mind a winter's total.
Neither December nor January this winter will be the warmest on record. But the combination of warmth, lack of intense cold, and until recently, a lack of snow has been really off the charts.
That's not to say winter still won't hit with a vengeance.
BRUTAL LATE WINTERS
Sometimes, winters that start out tropical turn into anything but by the time February rolls around. It's been plenty cold in past Februaries and Marches.
So yeah, if you're a fan of extreme winter cold, there's still time to get your rocks off. In Burlington, it's been below zero as late March 29. (in 1923).
The coldest temperature on record in Burlington came on February 12, 1979 and it's been in the 20s below as late as early March.
In the past week, we've certainly flipped to a snowier weather pattern, though it's still on the warm side. Most days over the past week have been around ten degrees warmer than average.
WARMTH TO FRIGID PAST
Warm winters can easily shift abruptly to cold. It's happened before. There's examples.
On February 25, 2017, the temperature reached 72 degrees in Burlington, by far the hottest temperature on record for the second month of the year. It felt like summer, never mind spring.
Just 17 days later, the Pi Day Blizzard struck. It dumped 30.4 inches of snow on Burlington, the city's second biggest snowstorm on record.
I can also point to a winter that was remarkably similar to this one up until this point. It illustrates how completely things can change. So let's harken back to the winter of 2006-07.
Each of the 18 days ending December 26 got above freezing. After a near average few days to close out the year, January came in like April.
Each of the first eight days of January, 2007 were in the 40s and 50s, peaking at a record high of 62 on January 6. It got a little cooler, but stayed mild through January 13
Then, starting in mid-January that winter, things started to get interesting. Temperatures stayed below freezing from January 15 through the end of the month, with the final seven days of the month all getting below zero.
February, 2007 stayed cold, with only three days barely getting above freezing and all 22 nights dropping to 10 degrees or lower. And who can forget the Valentine's Day blizzard that year, which deposited two to three feet of snow on Vermont in one day. It's still Burlington fifth largest snowstorm in the city's history.
The winter of 2007 extended well into March, with the coldest night of the winter in Burlington coming at the late date of March 7, when the temperature fell to a record 18 below zero. Subzero cold in Burlington came as late as March 21 that year.
Snowfall that winter amounted to 94.6 inches, well above normal. This, despite only 14.8 inches falling through January 13 in the winter of 2006-07.
We most certainly might not see a repeat of 2007 this year, but I bring it up to show it's possible.
There's other examples, too. January, 2005 began quite mild, but turned frigid. The third week of the month had daily temperatures below zero, and all but one of those in the teens below zero at Burlington.
WARMER TREND
So we know winter can abruptly take a colder turn, and this one might. However, in general, we've seen seeing fewer and fewer subzero days and night, at least judging from Burlington, Vermont data.
In the years, between the early 1930s through about 1980, Burlington would see on average about 22 to 25 days each winter that got to zero or below. There was a peak in the 1960s and early 1970s when there was usually 25 to 35 below zero days during a winter.
The most winter days in Burlington at or below zero in a single winter was 42 in 1919-1920.
The average number of winter days at or below zero dropped to very rough 15 between the 1980s and currently. But the number got more variable. For instance, the winter of 1993-94 saw 41 zero degree days, but the very next winter saw only 12.
Since 2002 - two decades - we've had ten winters with fewer than ten days below zero. In the 85 years between 1917 and 2002, there were only seven years with fewer than ten subzero days. Every winter from 1954 to 1990 had at least a dozen days at or below zero in Burlington.
It's interesting that before the 1960s there usually wasn't much snow on the ground during subzero cold spells. Often there was only one to three inches on the ground.
Starting in the 1960s and continuing through the 1970s, snow cover was usually much deeper during winter cold snaps. Snow cover nowadays is much more variable during spells of frigid winter weather.
Part of the decrease in winter time subzero days might be due to increased urbanization near the Burlington International Airport, where official temperature records have been taken since 1941. But climate change is very likely a major influence, too.
This trend will almost certainly continue. Who knows? We might have a stunningly frigid February this year. Anything could happen. But the chances of intense winter cold are declining as the years go by.
I expect in the future, we'll have more winters like 2002, when subzero cold seemed like ancient history.
