Wind Chill Calculator 2026
Wind Chill Calculator
Enter the air temperature and wind speed to see what it feels like outside — and how fast frostbite can set in. Extreme wind chill is one of the top reasons schools call snow days.
Uses the official National Weather Service wind chill formula. Valid for temperatures at or below 50°F (10°C) and wind speeds above 3 mph (5 km/h). This is a weather estimate — always confirm school closures with your school district. Try our Snow Day Predictor to see your closure chance.
What Is Wind Chill?
Wind chill is the "feels-like" temperature — the rate at which wind strips heat away from exposed skin, making the air feel colder than the thermometer reads. The faster the wind blows, the quicker your body loses heat. For example, a 10°F day with 20 mph wind can feel like -9°F on exposed skin.
How Wind Chill Causes School Closures
Many school districts close or delay classes when wind chills reach roughly -20°F to -30°F, because of the frostbite risk for kids waiting at bus stops. Even without fresh snow, dangerously cold air alone can shut down an entire district. Check our Snow Day Predictor to see your school's closure chance, and read how it works to understand how cold weather affects the forecast.
The Wind Chill Formula
This calculator uses the official National Weather Service wind chill formula, which combines air temperature and wind speed to estimate the feels-like temperature. The formula is valid for temperatures at or below 50°F and wind speeds above 3 mph — outside that range, wind chill has little meaningful effect.
Frostbite Times by Wind Chill
General guidance from the National Weather Service on how quickly frostbite can set in at different wind chills:
| Wind Chill | Frostbite Risk |
|---|---|
| 32°F and above | Minimal risk |
| 16–31°F | Use caution — cover exposed skin |
| 0–15°F | Frostbite possible on exposed skin within 30 minutes |
| -19 to 0°F | Frostbite can occur in 30 minutes or less |
| -34 to -20°F | Frostbite can occur in about 10 minutes |
| Below -35°F | Frostbite can occur in about 5 minutes |
Wind Chill Safety Tips
- Cover all exposed skin — wear a hat, scarf, mittens, and a face covering in extreme cold.
- Dress in layers, with a wind-resistant outer layer to block the wind.
- Limit time outdoors when wind chills are dangerously low.
- Watch for numbness, tingling, or white or gray skin — early signs of frostbite.
Frequently Asked Questions
At what wind chill do schools close?
It varies by district, but many use wind chills around -20°F to -30°F as a threshold for closing or delaying school. Always confirm closures with your local school district.
What is the difference between temperature and wind chill?
The air temperature is what the thermometer reads; wind chill is how cold it actually feels on exposed skin because wind strips heat from your body. Higher winds make the same temperature feel much colder.
Can wind chill close school without snow?
Yes. Extreme wind chill alone is one of the most common reasons schools close or delay, since frostbite can set in quickly for kids waiting at bus stops — even on a clear, sunny morning.
Is the wind chill formula the same in Canada?
Canada uses a slightly different wind chill formula, but the resulting values are very close. This calculator uses the U.S. National Weather Service formula.
How accurate is this calculator?
It is an estimate based on the official National Weather Service formula — it is not a medical diagnosis or an official school-closure decision. Always check your local forecast and school district announcements.