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 Idaho reference stations
Station
Coldest week
Normal low
Coldest night, last 10 winters
First freeze
Record low
BoiseBoise Air Terminal, USW00024131
Dec 24 to 30
24°F
−11°FJan 6, 2017
Oct 23
−25°FDec 22, 1990records since 1940
PocatelloPocatello Regional Airport, USW00024156
Dec 23 to 29
16°F
−22°FJan 6, 2017
Sep 29
−33°FFeb 1, 1985records since 1939
Idaho FallsIdaho Falls KIFI, USC00104455
Dec 28 to Jan 3
16°F
−24°FJan 30, 2023
Oct 9
−34°FFeb 1, 1985records since 1952
Coeur d'AleneCoeur d'Alene, USC00101956
Dec 22 to 28
25°F
−12°FJan 13, 2024
Oct 15
−30°FJan 30, 1950records since 1895
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 Boise 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 4 Idaho reference stations.
At Boise it is usually Dec 24 to 30, with a normal low of 24°F. At the other reference stations: Pocatello Dec 23 to 29 (16°F), Idaho Falls Dec 28 to Jan 3 (16°F) and Coeur d'Alene Dec 22 to 28 (25°F). These are NOAA's 1991 to 2020 daily normals.
The normal low at Boise reaches 32°F around Nov 15. The first actual freeze came around Oct 23 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 Boise was −11°F on Jan 6, 2017, and the coldest night of a typical winter there was 7°F. Elsewhere: Pocatello −22°F on Jan 6, 2017, Idaho Falls −24°F on Jan 30, 2023 and Coeur d'Alene −12°F on Jan 13, 2024. The record at the Boise station is −25°F, on Dec 22, 1990, in daily records since 1940.
At Boise a typical recent winter brings 105 nights at 32°F or colder and 18 at 20°F 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 Boise Air Terminal (USW00024131), Pocatello Regional Airport (USW00024156), Idaho Falls KIFI (USC00104455) and Coeur d'Alene (USC00101956). 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.
