December 2020 Climate Review

...PRELIMINARY DECEMBER 2020 NORTHERN AND EASTERN MAINE MONTHLY
CLIMATE NARRATIVE...

December 2020 finished with well above average temperatures and
above average precipitation.

Following on the heels of a very mild November, December was
another very mild month. Temperatures averaged from 6 to 8
degrees above the 30-year average. It was a top 10 warmest
December at all of the long term climate sites. In Caribou,
Bangor, and Millinocket it was the 4th warmest December on record.
In Houlton, it was the 3rd warmest December on record.

The big news story was the all-time winter record warmth on the
1st of the month. Caribou had a high of 60 degrees (F), which not
only broke the daily and monthly temperature records, but
surpassed the all-time meteorological winter high temperature of
59 degrees (F) set on February 20, 1994.

Houlton also observed a high of 60 degrees (F), which although not
an all-time record for the winter was a record high for the month
of December. The old record was 59 degrees (F) set on December
11, 1969. In Millinocket, the high of 60 degrees (F) was the 3rd
warmest December day on record. In Bangor, the high of 61 degrees
(F) broke the daily record of 59 (F) set in 2006.

Temperatures were consistently above average, with only one cold
snap from December 15th-19th when temperatures were below
average. During this stretch of colder weather Caribou had 4
nights when the low fell below zero, but the lows did not even
come close to record lows.

Precipitation was above average and ranged from 110 to 200 percent
of normal. The most significant departures were in northern
Washington County and central and southern Piscataquis County.
Snowfall was slightly above average in Caribou with a total of
26.3 inches, which was 2.6 inches above average. In Bangor, 5.7
inches of snow as observed, which was 8.7 inches below average.
Most areas Downeast had well below average snowfall with much of
the monthly precipitation falling in the form of rain.

In Caribou, the combination of rain and record warmth on Christmas
Day caused the snow depth to drop to zero by the morning of the
26th. By the end of the month, the snow depth was back up to 5
inches, which is well below average for the end of December.
Snow depth at the end of the month ranged from 3 to 6 inches from
northern Washington County north to the Saint John Valley, with
bare ground in most areas Downeast, in Bangor, and along the
coast.

The outlook from the Climate Prediction Center for January calls
for an increased likelihood of both above average temperatures and
precipitation. The coldest average temperatures of the year are
observed in mid to late January. The average high in Caribou drops
to 19F by the 18th and the average low 1 above. Average snowfall
in Caribou is 25.1 inches. In Bangor, the average high drops to
27F by mid month and the average low to 6 above. On average, there
is 19.2 inches of snow.