Cold Snap Forecast for Maine: The Next Arctic Blast
In Portland the coldest week is usually Jan 23 to 29, with a normal low of 15°F, and the coldest night of the last 10 winters was −17°F on Jan 1, 2018.
Reading the National Weather Service forecast for Portland.
Normals and records at Portland International Jetport
The week with the lowest normal low at each reference station, from NOAA’s 1991 to 2020 normals, beside the coldest night of the last 10 winters, the median first freeze and the record low.
The coldest week and the coldest nights at Maine reference stations
Station
Coldest week
Normal low
Coldest night, last 10 winters
First freeze
Record low
PortlandPortland International Jetport, USW00014764
Jan 23 to 29
15°F
−17°FJan 1, 2018
Oct 16
−39°FFeb 16, 1943records since 1940
BangorBangor International Airport, USW00014606
Jan 23 to 29
8°F
−24°FDec 31, 2017
Oct 10
−30°FFeb 2, 1962records since 1953
CaribouCaribou Municipal Airport, USW00014607
Jan 23 to 29
1°F
−30°FJan 27, 2022
Sep 30
−41°FFeb 1, 1955records since 1948
Normals from NOAA NCEI; nightly lows from GHCN-Daily, the winters of 2016 to 2017 through 2025 to 2026.
The panel at the top of this page sets the next 7 nights at Portland against the normal low for each date and adds the Climate Prediction Center outlook for the two weeks after. Enter a ZIP for your own town; it uses the nearest of the 3 Maine reference stations.
At Portland it is usually Jan 23 to 29, with a normal low of 15°F. At the other reference stations: Bangor Jan 23 to 29 (8°F) and Caribou Jan 23 to 29 (1°F). These are NOAA's 1991 to 2020 daily normals.
The normal low at Portland reaches 32°F around Nov 15 and 20°F around Dec 25. The first actual freeze came around Oct 16 in the median of the last 10 winters, weeks ahead of the normal, because one clear calm night can run far below the average.
The coldest night of the last 10 winters at Portland was −17°F on Jan 1, 2018, and the coldest night of a typical winter there was −5°F. Elsewhere: Bangor −24°F on Dec 31, 2017 and Caribou −30°F on Jan 27, 2022. The record at the Portland station is −39°F, on Feb 16, 1943, in daily records since 1940.
At Portland a typical recent winter brings 137 nights at 32°F or colder, 58 at 20°F or colder and 3 at zero or colder, the median of the last 10 seasons.
Each night's forecast low is compared with the NOAA normal low for that date at the nearest reference station. A night 20 or more degrees below normal is an arctic blast, and so is a night below zero where the normal low is 10°F or warmer. A night 10 to 19 below is a cold snap. A night 5 or more below, or a week that runs 3 or more below on average, is colder than normal, and a week 5 or more above is mild.
The normal lows and coldest weeks are NOAA's 1991 to 2020 daily climate normals for Portland International Jetport (USW00014764), Bangor International Airport (USW00014606) and Caribou Municipal Airport (USW00014607). The recent winters, first dates and records come from the same stations' daily lows in NOAA's GHCN-Daily archive, the winters of 2016 to 2017 through 2025 to 2026. The 7 night forecast is the National Weather Service's and the outlook is the Climate Prediction Center's.
