Wind Chill Calculator

Wind chill is the perceived decrease in air temperature felt on exposed skin due to wind. Moving air strips heat from the body faster than still air, making it feel colder than the actual thermometer reading. This calculator uses the official formulas adopted by the US National Weather Service and Environment Canada.

NWS Wind Chill Formula (Fahrenheit, wind in mph):

WC = 35.74 + 0.6215T − 35.75(V^0.16) + 0.4275T(V^0.16)

Environment Canada Formula (Celsius, wind in km/h):

WC = 13.12 + 0.6215T − 11.37(V^0.16) + 0.3965T(V^0.16)

What each variable means:

• T — the actual air temperature measured by a thermometer, in °F or °C.
• V — wind speed at face height (about 1.5 meters), in mph or km/h.
• WC — the resulting wind chill temperature, representing what it “feels like.”

Valid range: The formula is designed for temperatures at or below 50°F (10°C) and wind speeds above 3 mph (5 km/h). Above these thresholds, wind chill equals the air temperature.

Practical example (Imperial): Air temperature = 20°F, wind speed = 15 mph. V^0.16 = 15^0.16 = 1.534. WC = 35.74 + 0.6215(20) − 35.75(1.534) + 0.4275(20)(1.534) = 35.74 + 12.43 − 54.84 + 13.12 = 6.5°F. It feels almost 14 degrees colder than the actual temperature.

Practical example (Metric): Air temperature = −5°C, wind speed = 25 km/h. WC = 13.12 + 0.6215(−5) − 11.37(25^0.16) + 0.3965(−5)(25^0.16) = approximately −11.4°C.

Frostbite risk reference:

• Wind chill at or below 0°F (−18°C): frostbite possible in 30 minutes
• Wind chill at or below −18°F (−28°C): frostbite possible in 10 minutes
• Wind chill at or below −40°F/°C: frostbite possible in as little as 5 minutes

Tips: Cover all exposed skin when wind chill is below 0°F (−18°C). Fingers, toes, ears, and nose are most vulnerable. Dressing in layers traps insulating air and is more effective than a single thick layer. Wet skin loses heat even faster, so keep dry in cold windy conditions.