Wind Chill Calculator
Why Cold Air Feels Colder When the Wind Picks Up
Wind chill describes how quickly exposed skin loses heat when moving air strips away the thin insulating layer your body warms around itself. The same air temperature can feel dramatically different at 3 mph versus 25 mph, which is why the National Weather Service publishes an official formula rather than leaving "feels like" temperature to guesswork — it directly affects frostbite timing and cold-weather safety warnings.
The Formula
T is air temperature in °F and V is wind speed in mph. This is the National Weather Service's official wind chill equation, valid only for temperatures at or below 50°F and wind speeds of 3 mph or greater — outside that range, wind has negligible additional cooling effect or the formula's underlying model breaks down.
Worked Examples
| Air temperature | Wind speed | Wind chill |
|---|---|---|
| 30°F | 10 mph | 21.25°F |
| 20°F | 15 mph | 6.22°F |
| 0°F | 20 mph | −22.0°F |
The formula is not linear — wind chill drops faster at higher wind speeds initially, then levels off, which is why the exponent on wind speed is a fraction (0.16) rather than a whole number.
Where This Matters
- Frostbite timing — the NWS ties specific wind chill thresholds to estimated time-to-frostbite for exposed skin, informing cold weather advisories and warnings.
- Outdoor work and activity planning — construction crews, event organizers, and outdoor sports programs use wind chill thresholds to decide when conditions require breaks, extra gear, or cancellation.
- Dressing appropriately — knowing the effective temperature rather than just the thermometer reading helps you choose the right layers before heading outside.
How to Use This Calculator
- Enter the Air Temperature in °F (must be 50°F or below).
- Enter the Wind Speed in mph (must be 3 mph or greater).
- Select Calculate to see the wind chill temperature.
Related Calculations
For hot-weather conditions, use the Heat Index Calculator to find the feels-like temperature, or check the Humidity Calculator to work out relative humidity from a dew point reading.