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 Colorado reference stations
Station
Coldest week
Normal low
Coldest night, last 10 winters
First freeze
Record low
DenverDenver International Airport, USW00003017
Dec 17 to 23
18°F
−24°FDec 22, 2022
Oct 12
−24°FDec 22, 2022records since 1994
Colorado SpringsColorado Springs Municipal Airport, USW00093037
Dec 22 to 28
18°F
−16°FFeb 15, 2021
Oct 10
−27°FFeb 1, 1951records since 1948
Grand JunctionGrand Junction Walker Field, USW00023066
Dec 29 to Jan 4
16°F
−4°FJan 2, 2019
Oct 20
−23°FJan 13, 1963records since 1900
AlamosaAlamosa San Luis Airport, USW00023061
Jan 2 to 8
−2°F
−36°FJan 7, 2017
Sep 15
−50°FJan 28, 1948records 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 Denver 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 Colorado reference stations.
At Denver it is usually Dec 17 to 23, with a normal low of 18°F. At the other reference stations: Colorado Springs Dec 22 to 28 (18°F), Grand Junction Dec 29 to Jan 4 (16°F) and Alamosa Jan 2 to 8 (−2°F). These are NOAA's 1991 to 2020 daily normals.
The normal low at Denver reaches 32°F around Oct 30 and 20°F around Dec 4. The first actual freeze came around Oct 12 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 Denver was −24°F on Dec 22, 2022, and the coldest night of a typical winter there was −12°F. Elsewhere: Colorado Springs −16°F on Feb 15, 2021, Grand Junction −4°F on Jan 2, 2019 and Alamosa −36°F on Jan 7, 2017. The record at the Denver station is −24°F, on Dec 22, 2022, in daily records since 1994.
At Denver a typical recent winter brings 153 nights at 32°F or colder, 61 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 Denver International Airport (USW00003017), Colorado Springs Municipal Airport (USW00093037), Grand Junction Walker Field (USW00023066) and Alamosa San Luis Airport (USW00023061). 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.
