Iowa Snow Day Calculator: Chances & Closure Norms
What closes Iowa schools? Snowday's Iowa calculator typically flags a snow day at about 5–6 inches of snow, and often less when wind creates blizzard conditions across open farm country. Des Moines averages about 35 inches a year. Enter your ZIP code above for tomorrow's chance.
Snow day calculator
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Result
Your forecast appears here. Enter a ZIP code or city above and press Calculate snow day chance.
Fun estimate only — always follow your school district’s official announcements.
How Iowa districts decide snow days
The usual snow trigger is 5 to 6 inches overnight, dropping to 3 or 4 when winds gust above 30 mph and visibility collapses. Rural districts with 60-mile bus loops close faster than Des Moines and Cedar Rapids metro districts for exactly this reason: the last gravel road determines the day.
Blizzard Warnings from the Des Moines NWS office close schools almost automatically — the January 2024 ground blizzard closed districts statewide with barely any fresh snow. Cold days join in when wind chills approach −25 to −30 °F, protecting farm-route students who wait at lane ends.
Average snowfall in Iowa
| Place | Avg. snow per year |
|---|---|
| Des Moines | ≈ 35 in/yr |
| Dubuque | ≈ 42 in/yr |
| Sioux City | ≈ 35 in/yr |
Averages are approximate NOAA/NCEI 1991–2020 climate normals, rounded. Northeast Iowa’s driftless terrain near Dubuque catches a little more snow and holds ice longer than the flat northwestern counties.
The storm Iowa remembers
The Children’s Blizzard of 1888. On January 12, 1888, an Arctic front slammed the Midwest on a mild, clear morning — the “Schoolhouse Blizzard” or Children’s Blizzard. An estimated 235 people died, many of them children caught walking home from one-room schools across the plains, and the storm is remembered as the founding event of American school-closure safety thinking.
Using the calculator in Iowa
Snowday weights Iowa with a 4.5-inch baseline and real bonuses for wind and cold hours. Open the snow day calculator, enter ZIP 50309 for Des Moines, and set the strictness slider for your district. For the full picture, open the snow day calculator and see how commute-hour snowfall, cold, and wind combine into tomorrow’s percent chance — free, instant, no sign-up.
Last updated: October 2026