Cold Day Calculator
Will extreme cold close school tomorrow?
Enter your ZIP code. The result includes the forecast wind chill at bus time (5–8 AM) and the cold line where closures usually start in your area.
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Snow by hour
From the National Weather Service forecast, updated hourly. Estimate only. Your district makes the call.
Where cold closes schools
Our model's cold line for each city: the wind chill where a closure becomes likely, set from the normal December–February low. Delays start about 5°F warmer.
| City | Normal winter low | Cold line (model) |
|---|---|---|
| Minneapolis, MN | 12°F | −33°F |
| Fargo, ND | 4°F | −40°F |
| Sioux Falls, SD | 12°F | −33°F |
| Madison, WI | 13°F | −32°F |
| Chicago, IL | 23°F | −22°F |
| Des Moines, IA | 17°F | −28°F |
| Buffalo, NY | 21°F | −24°F |
| Denver, CO | 18°F | −27°F |
| Boston, MA | 26°F | −20°F |
| New York, NY | 30°F | −20°F |
| Atlanta, GA | 35°F | −20°F |
Normal low: NOAA 1991–2020 December–February mean minimum. The cold line is our model's estimate, not a district policy.
Cold day questions
What wind chill closes schools?
There is no national rule. Districts in the coldest states tolerate far colder mornings than districts in milder places, where much less cold can delay buses. The calculator sets a local cold line from your area's normal winter low (NOAA 1991–2020) and compares it with the forecast wind chill at bus time.
What is a cold day?
A school closure or delay because of extreme cold rather than snow: buses, frozen pipes and children waiting outdoors at dangerous wind chills. Some districts publish a written cold-weather policy; check yours.
Which NWS alerts matter for cold days?
Extreme Cold Warning and Extreme Cold Watch, and the lower Cold Weather Advisory. The older Wind Chill Warning and Wind Chill Advisory are no longer on the NWS alert list. The calculator raises the chance when one is active for your county.