Cold Snap Forecast for Iowa: The Next Arctic Blast
In Des Moines the coldest week is usually Jan 18 to 24, with a normal low of 13°F, and the coldest night of the last 10 winters was −20°F on Jan 30, 2019.
Reading the National Weather Service forecast for Des Moines.
Normals and records at Des Moines International Airport
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 Iowa reference stations
Station
Coldest week
Normal low
Coldest night, last 10 winters
First freeze
Record low
Des MoinesDes Moines International Airport, USW00014933
Jan 18 to 24
13°F
−20°FJan 30, 2019
Oct 23
−26°FFeb 3, 1996records since 1945
Sioux CitySioux City Gateway Airport, USW00014943
Jan 15 to 21
10°F
−28°FFeb 16, 2021
Oct 11
−28°F3 times, last on Feb 16, 2021records since 1940
WaterlooWaterloo Municipal Airport, USW00094910
Jan 18 to 24
10°F
−31°FJan 31, 2019
Oct 13
−34°FTwice, last on Jan 16, 2009records since 1950
DubuqueDubuque Regional Airport, USW00094908
Jan 19 to 25
10°F
−31°FJan 31, 2019
Oct 14
−31°FJan 31, 2019records since 1951
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 Des Moines 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 Iowa reference stations.
At Des Moines it is usually Jan 18 to 24, with a normal low of 13°F. At the other reference stations: Sioux City Jan 15 to 21 (10°F), Waterloo Jan 18 to 24 (10°F) and Dubuque Jan 19 to 25 (10°F). These are NOAA's 1991 to 2020 daily normals.
The normal low at Des Moines reaches 32°F around Nov 12 and 20°F around Dec 14. 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 Des Moines was −20°F on Jan 30, 2019, and the coldest night of a typical winter there was −12°F. Elsewhere: Sioux City −28°F on Feb 16, 2021, Waterloo −31°F on Jan 31, 2019 and Dubuque −31°F on Jan 31, 2019. The record at the Des Moines station is −26°F, on Feb 3, 1996, in daily records since 1945.
At Des Moines a typical recent winter brings 134 nights at 32°F or colder, 55 at 20°F or colder and 10 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 Des Moines International Airport (USW00014933), Sioux City Gateway Airport (USW00014943), Waterloo Municipal Airport (USW00094910) and Dubuque Regional Airport (USW00094908). 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.
