What is wind chill and how is it calculated?

Wind chill is the "feels-like" temperature accounting for heat loss caused by wind. Moving air carries away body heat faster than still air, making it feel colder. The official Environment Canada / NOAA formula (2001): Wind Chill = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965TV^0.16, where T is temperature in °C and V is wind speed in km/h. This formula was validated with human subjects and replaced the old Siple-Passel formula.

What temperature and wind conditions cause frostbite?

Frostbite risk by wind chill: above -10°C (14°F) = low risk with normal clothing; -10 to -25°C (14 to -13°F) = frostbite possible in 10-30 minutes on exposed skin; -25 to -35°C (-13 to -31°F) = frostbite in 5-10 minutes; -35 to -45°C (-31 to -49°F) = frostbite in 2-5 minutes; below -45°C (-49°F) = frostbite in under 2 minutes, extreme danger. Protect face, fingers, toes, ears, and nose first.

Does wind chill apply in warm weather?

No — wind chill only applies when the air temperature is at or below 10°C (50°F). In warm weather, wind has the opposite effect: it cools you through evaporative cooling when you are sweating, but the "feels warmer" effect of high humidity is captured by the Heat Index (apparent temperature) instead. Wind chill and heat index are separate calculations for opposite weather conditions.

What is the difference between wind chill and feels-like temperature?

Wind chill is the cold-side feels-like temperature — accounting for wind in cold weather. The Heat Index is the hot-side feels-like temperature — accounting for humidity in hot weather. "Feels Like" or "apparent temperature" is the general term covering both. Some weather apps combine both into a single "feels like" number: in cold conditions it shows wind chill; in hot conditions it shows heat index.

Why does wind chill use V^0.16 in the formula?

The exponent 0.16 in the wind chill formula reflects that wind speed has a diminishing return on cooling effect. Doubling wind speed does not double the cooling — the relationship is sublinear (logarithmic-ish). The formula was derived empirically from human test subjects walking in cold-wind chambers, where heat loss measurements were fitted to the V^0.16 power law.

How should I dress for different wind chill levels?

Clothing guidance by wind chill: 0 to -10°C (32 to 14°F): warm coat, hat, gloves. -10 to -20°C (14 to -4°F): insulated coat, windproof layer, thermal hat, mittens. -20 to -35°C (-4 to -31°F): all layers + balaclava, face protection, wool or down insulation. Below -35°C (-31°F): minimize outdoor exposure; face, hands, and toes can freeze in minutes. The key risk is exposed skin — cover all of it in extreme cold.

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Wind Chill Calculator

Wind chill (feels-like temperature) is calculated using the Environment Canada / NOAA 2001 formula: Wind Chill = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965TV^0.16, where T is temperature in °C and V is wind speed in km/h. Wind chill applies only at temperatures ≤ 10°C (50°F) and wind speeds ≥ 3 km/h (1.8 mph). At -15°C with 40 km/h wind, the feels-like temperature is approximately -25°C.

Calculate the wind chill (feels-like temperature) based on air temperature and wind speed. Uses the official Environment Canada / NOAA 2001 formula. Supports Celsius/km/h and Fahrenheit/mph. Shows frostbite risk level and exposure safety guidelines.

Units

Quick Examples

Conditions

Temperature (°C)

Wind chill applies at 10°C (50°F) or below

Wind Speed (km/h)

Wind chill applies at 3 km/h or more

Wind Chill Reference

Wind Chill	Risk Level
Above 0°C / 32°F	Chilly — dress in layers
0 to -10°C / 32 to 14°F	Cold — protect exposed skin
-10 to -25°C / 14 to -13°F	Very cold — frostbite in 10-30 min
-25 to -35°C / -13 to -31°F	Extremely cold — frostbite in 5-10 min
-35 to -45°C / -31 to -49°F	Frostbite in 2-5 minutes
Below -45°C / -49°F	Extreme danger — frostbite under 2 min

Formula: Environment Canada / NOAA joint standard (2001). Valid for temperatures at or below 10°C (50°F) and wind speeds above 3 km/h (1.8 mph).

How to Use

1
Select your units
Choose Celsius / km/h (Canada, most countries) or Fahrenheit / mph (United States). Click a quick example to pre-fill realistic winter conditions.
2
Enter the temperature
Type the actual air temperature. Wind chill only applies at or below 10°C (50°F). Above this threshold the calculator will note there is no wind chill effect.
3
Enter the wind speed
Type the wind speed in your selected unit. Wind chill applies at 3 km/h (1.8 mph) or higher. Calm conditions show no wind chill effect.
4
Read the result
The feels-like temperature appears with a color-coded risk level (chilly, cold, very cold, extremely cold, extreme hazard) and a frostbite exposure time estimate.

Frequently Asked Questions

What is wind chill and how is it calculated?: Wind chill is the "feels-like" temperature accounting for heat loss caused by wind. Moving air carries away body heat faster than still air, making it feel colder. The official Environment Canada / NOAA formula (2001): Wind Chill = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965TV^0.16, where T is temperature in °C and V is wind speed in km/h. This formula was validated with human subjects and replaced the old Siple-Passel formula.
What temperature and wind conditions cause frostbite?: Frostbite risk by wind chill: above -10°C (14°F) = low risk with normal clothing; -10 to -25°C (14 to -13°F) = frostbite possible in 10-30 minutes on exposed skin; -25 to -35°C (-13 to -31°F) = frostbite in 5-10 minutes; -35 to -45°C (-31 to -49°F) = frostbite in 2-5 minutes; below -45°C (-49°F) = frostbite in under 2 minutes, extreme danger. Protect face, fingers, toes, ears, and nose first.
Does wind chill apply in warm weather?: No — wind chill only applies when the air temperature is at or below 10°C (50°F). In warm weather, wind has the opposite effect: it cools you through evaporative cooling when you are sweating, but the "feels warmer" effect of high humidity is captured by the Heat Index (apparent temperature) instead. Wind chill and heat index are separate calculations for opposite weather conditions.
What is the difference between wind chill and feels-like temperature?: Wind chill is the cold-side feels-like temperature — accounting for wind in cold weather. The Heat Index is the hot-side feels-like temperature — accounting for humidity in hot weather. "Feels Like" or "apparent temperature" is the general term covering both. Some weather apps combine both into a single "feels like" number: in cold conditions it shows wind chill; in hot conditions it shows heat index.
Why does wind chill use V^0.16 in the formula?: The exponent 0.16 in the wind chill formula reflects that wind speed has a diminishing return on cooling effect. Doubling wind speed does not double the cooling — the relationship is sublinear (logarithmic-ish). The formula was derived empirically from human test subjects walking in cold-wind chambers, where heat loss measurements were fitted to the V^0.16 power law.
How should I dress for different wind chill levels?: Clothing guidance by wind chill: 0 to -10°C (32 to 14°F): warm coat, hat, gloves. -10 to -20°C (14 to -4°F): insulated coat, windproof layer, thermal hat, mittens. -20 to -35°C (-4 to -31°F): all layers + balaclava, face protection, wool or down insulation. Below -35°C (-31°F): minimize outdoor exposure; face, hands, and toes can freeze in minutes. The key risk is exposed skin — cover all of it in extreme cold.