Wind Chill Calculator -- Feels-Like Temperature

Calculate Wind Chill

Wind chill measures how cold it actually feels when wind is factored in. Enter the air temperature and wind speed to see the wind chill temperature, danger level, and frostbite risk.

Wind Chill Reference Table

Wind chill values for common temperature and wind speed combinations. Colors indicate danger level.

Source: National Weather Service wind chill chart. Frostbite times are approximate for exposed skin.

The NWS Wind Chill Formula

The current wind chill formula was developed by the National Weather Service (NWS) and Environment Canada in 2001, replacing the older Siple-Passel formula. It is based on a model of heat loss from the human face.

Fahrenheit formula

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

Where T = air temperature in °F and V = wind speed in mph.

Celsius formula

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

Where T = air temperature in °C and V = wind speed in km/h.

When does the formula apply?

• Air temperature must be 50°F (10°C) or below
• Wind speed must be above 3 mph (4.8 km/h)
• The formula models heat loss from exposed human skin, specifically the face
• At calm winds, the wind chill equals the actual air temperature

Understanding Frostbite Risk

Frostbite occurs when skin and underlying tissue freeze due to prolonged cold exposure. Wind accelerates this process by stripping away the thin layer of warm air near the skin.

Safety tips for cold and windy conditions

• Layer up: Wear multiple layers -- a moisture-wicking base, insulating middle, and windproof outer layer.
• Cover exposed skin: Ears, nose, cheeks, and fingers are most vulnerable to frostbite.
• Stay dry: Wet clothing loses insulating value and increases heat loss dramatically.
• Limit time outdoors: Take breaks indoors when wind chill drops below 0°F (-18°C).
• Watch for warning signs: Numbness, white or grayish-yellow skin, and skin that feels unusually firm or waxy are signs of frostbite.
• Stay hydrated: Cold air is dry, and dehydration increases frostbite risk.
• Check conditions before going out: Wind can change quickly, especially in open terrain.

Wind Chill vs. Heat Index

Wind chill and heat index are opposite sides of the same concept -- both measure how temperature feels rather than what a thermometer reads.

Frequently Asked Questions

What is wind chill?

Wind chill is the perceived decrease in air temperature felt by the body due to wind. Moving air strips away the insulating layer of warm air near your skin, making it feel colder than the actual temperature. The wind chill index estimates how cold it feels on exposed human skin.

What is the wind chill formula?

The NWS wind chill formula (2001) is: WC = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), where T is the air temperature in °F and V is the wind speed in mph. This formula is valid for temperatures at or below 50°F and wind speeds above 3 mph.

When does frostbite occur from wind chill?

Frostbite can occur within 30 minutes when wind chill is -18°F (-28°C) or lower. At wind chills of -45°F (-43°C), frostbite can occur in as little as 10 minutes. At -60°F (-51°C) or below, frostbite can occur in 5 minutes or less on exposed skin.

Does wind chill apply in warm weather?

No. The NWS wind chill formula only applies when the air temperature is 50°F (10°C) or below and wind speed is above 3 mph (4.8 km/h). In warm weather, the heat index is used instead to measure how hot it feels based on temperature and humidity.

Can wind chill make water freeze faster?

Wind chill affects how quickly heat is lost from warm objects (including skin), but it cannot make the air temperature itself drop below the thermometer reading. Water will not freeze at a higher temperature because of wind chill. However, wind can accelerate cooling of a warm object (like a cup of water) toward the actual air temperature.

Why was the wind chill formula updated in 2001?

The original Siple-Passel formula from 1945 was based on experiments measuring how fast water froze in a plastic cylinder -- not on human skin. The 2001 NWS formula uses a model of heat loss from the human face, clinical trials, and modern understanding of heat transfer. It generally produces higher (less extreme) values than the old formula.

Does this calculator store my data?

No. All calculations run entirely in your browser. No data is sent to any server, and nothing is stored.

Related Tools

• Heat Index Calculator -- calculate feels-like temperature from heat and humidity
• Dew Point Calculator -- calculate dew point from temperature and humidity
• Temperature Unit Converter -- convert between Fahrenheit, Celsius, and Kelvin

Privacy & Limitations

Privacy: This calculator runs entirely in your browser. No personal data is transmitted or stored anywhere.

Limitations: The NWS wind chill formula applies only when air temperature is at or below 50°F (10°C) and wind speed is above 3 mph (4.8 km/h). Frostbite time estimates are approximate and vary by individual factors such as clothing, activity level, and health conditions. This tool is for informational purposes and should not replace official weather advisories.

Wind Chill Calculator FAQ