Cold Snap Forecast for Wyoming: The Next Arctic Blast
In Cheyenne the coldest week is usually Dec 17 to 23, with a normal low of 17°F, and the coldest night of the last 10 winters was −25°F on Dec 22, 2022.
Reading the National Weather Service forecast for Cheyenne.
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 Wyoming reference stations
Station
Coldest week
Normal low
Coldest night, last 10 winters
First freeze
Record low
CheyenneCheyenne, USW00024018
Dec 17 to 23
17°F
−25°FDec 22, 2022
Oct 6
−34°FFeb 8, 1936records since 1915
CasperCasper Natrona County Airport, USW00024089
Dec 19 to 25
14°F
−42°FDec 22, 2022
Sep 19
−42°FDec 22, 2022records since 1948
LaramieLaramie Regional Airport, USW00024022
Dec 20 to 26
9°F
−40°FJan 6, 2017
Sep 21
−50°FJan 12, 1963records since 1948
SheridanSheridan County Airport, USW00024029
Dec 24 to 30
11°F
−31°FJan 13, 2024
Oct 1
−37°FDec 24, 1983records 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 Cheyenne 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 Wyoming reference stations.
At Cheyenne it is usually Dec 17 to 23, with a normal low of 17°F. At the other reference stations: Casper Dec 19 to 25 (14°F), Laramie Dec 20 to 26 (9°F) and Sheridan Dec 24 to 30 (11°F). These are NOAA's 1991 to 2020 daily normals.
The normal low at Cheyenne reaches 32°F around Oct 22 and 20°F around Dec 2. The first actual freeze came around Oct 6 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 Cheyenne was −25°F on Dec 22, 2022, and the coldest night of a typical winter there was −14°F. Elsewhere: Casper −42°F on Dec 22, 2022, Laramie −40°F on Jan 6, 2017 and Sheridan −31°F on Jan 13, 2024. The record at the Cheyenne station is −34°F, on Feb 8, 1936, in daily records since 1915.
At Cheyenne a typical recent winter brings 166 nights at 32°F or colder, 71 at 20°F or colder and 7 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 Cheyenne (USW00024018), Casper Natrona County Airport (USW00024089), Laramie Regional Airport (USW00024022) and Sheridan County Airport (USW00024029). 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.
