Wind Chill Formula
Calculate how cold it feels when wind is factored in.
Used by weather services to warn about frostbite risk.
The Formula
Wind chill tells you how cold your skin feels when wind accelerates heat loss from your body. Even moderate wind can make temperatures feel dramatically colder and increase frostbite risk.
Variables
| Symbol | Meaning |
|---|---|
| WC | Wind chill temperature (°F) |
| T | Air temperature (°F) |
| V | Wind speed (mph) |
Metric version: WC = 13.12 + 0.6215T - 11.37V⁰·¹⁶ + 0.3965TV⁰·¹⁶ (T in °C, V in km/h). Valid when T ≤ 50°F (10°C) and V ≥ 3 mph (4.8 km/h).
Example 1
Temperature is 20°F (-7°C) with 25 mph wind
V⁰·¹⁶ = 25⁰·¹⁶ ≈ 1.738
WC = 35.74 + 0.6215(20) - 35.75(1.738) + 0.4275(20)(1.738)
WC = 35.74 + 12.43 - 62.13 + 14.86
WC ≈ 1°F (-17°C) — Frostbite possible in 30 minutes
Example 2
Temperature is 0°C with 30 km/h wind (metric formula)
V⁰·¹⁶ = 30⁰·¹⁶ ≈ 1.778
WC = 13.12 + 0.6215(0) - 11.37(1.778) + 0.3965(0)(1.778)
WC = 13.12 + 0 - 20.22 + 0
WC ≈ -7°C (feels significantly colder than the actual temperature)
When to Use It
Use the wind chill formula when:
- Assessing the risk of frostbite and hypothermia
- Planning outdoor activities in cold, windy conditions
- Issuing weather warnings for public safety
- Choosing appropriate clothing for winter conditions