January thaw continues much of this week, but is it normal?

Temperatures are above freezing this morning everywhere in New England from Caribou in Northern Maine to Bridgeport in southern Connecticut. If you are looking for a period constituting a January thaw, this is certainly a good candidate. We’ve had a cold month thus far, after a cold November and December. The first 12 days of January will show 8 below normal days and 4 above normal. If we average the days, the month is still turning out to be a cold one.

I hate the term normal or average when it comes to a lot of things, including weather. The idea precipitation and temperature are smooth curves throughout the year is a complete fallacy. The “average” temperatures for today are 36F for a high and 22F for a low. Those numbers are for Logan Airport, but give a good idea of the range for the date. An even less accurate “average” is precipitation. Yesterday’s average precipitation was just over a tenth of an inch. This is calculated by taking dividing the average amount of rainfall for the 30 Januarys between 1981 and 2000 and dividing that number by 31. Our rainfall yesterday was about 5 times higher than average, but is meaningless, because snow and rain are not spread evenly across any month.


In this part of the country the temperature and precipitation are rarely average. Since 2009, there have been 7 January days where the average temperature for the day was, average. Last year there wasn’t one average day in January and this year we haven’t had any either. Another way to look at this is to say out of 133 January days since 2009, only 7 have been “average”.

Yesterday began a stretch of above normal temperatures some of us call a January thaw. Whether this thaw is a real or perceived phenomenon is open to interpretation. Several years ago three meteorologists from Cornell University and the National Weather Service did a study on whether the January Thaw was a “statistical phantom”. The report can be viewed here. It’s quite technical from a statistical standpoint. One part of the conclusion speaks to the absence of a “physical rational” and the “results leave one with little reason to look beyond simple statistical sampling variations as the cause for the January thaw.” Real or perceived, a thaw in January has been part of weather lore for centuries.

Temperatures are going to remain on the milder side of average much of this week before cooling off towards the weekend and beyond the 20th of the month. According to the latest guidance from the computer models, snowfall over the next 10 days looks to be low. I feel more confident about the temperature forecast as opposed to that of precipitation. It takes a much smaller shift in the upper level winds to bring us a rain or snowstorm than it does to vary the temperatures.


This afternoon will feature highs in the 40s and Monday will be even milder with a comfortable reading around 50F in the afternoon. While reading this high are not good for snow lovers or for keeping the ice on the lakes and ponds, they are terrific for saving on heating costs and general piece of mind. A small storm is going to bring rain to the area Tuesday. The cold air will remain locked in Canada during this next event keeping the precipitation in liquid form. There could be some snow showers as the storm ends later Tuesday evening.

monday highs2.jpg

If someone comments to you today this weather just isn’t “normal” for January, tell them it certainly is and to just enjoy it. The cold isn’t finished; it’s just taking an atmospheric rest.

I’ll be updating my forecast on Twitter @growingwisdom, please follow me there.


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