# Wind Chill Calculator

Calculate wind chill temperature with the official NWS formula. Enter air temperature and wind speed to find the feels-like temperature and frostbite risk.

## What this calculates

Wind chill describes how cold it actually feels on exposed skin when the wind is factored in. A 20°F day with 15 mph winds feels like 6°F. The National Weather Service formula accounts for heat loss from the body caused by wind, and it only applies when the temperature is 50°F or below and wind speed is above 3 mph.

## Inputs

- **Air Temperature** (°F) — min -100, max 50 — Air temperature (must be 50°F / 10°C or below for wind chill to apply).
- **Wind Speed** (mph) — min 0 — Wind speed (must be above 3 mph / 4.8 km/h for wind chill to apply).

## Outputs

- **Wind Chill** (°F) — Feels-like temperature in Fahrenheit.
- **Wind Chill** (°C) — Feels-like temperature in Celsius.
- **Frostbite Risk** — formatted as text — Estimated frostbite risk based on wind chill.

## Details

The NWS Wind Chill formula (updated in 2001) is:

WC = 35.74 + 0.6215T - 35.75V0.16 + 0.4275TV0.16

  - T = air temperature in °F

  - V = wind speed in mph

  - WC = wind chill temperature in °F

For example, at 0°F with a 25 mph wind, the wind chill is about -24°F. That means exposed skin loses heat as fast as it would in calm air at -24°F. At that level, frostbite can develop on exposed skin within 15 minutes.

The formula was developed using human trial data where volunteers had temperature sensors on their faces while walking into the wind. It replaced the older Siple-Passel index from 1945, which overestimated heat loss because it was based on water freezing in a plastic container, not human skin.

## Frequently Asked Questions

**Q: When does the wind chill formula apply?**

A: The NWS wind chill formula is valid when the air temperature is 50°F (10°C) or below and wind speed is above 3 mph (4.8 km/h). Outside these ranges, the wind chill equals the actual air temperature.

**Q: Can wind chill make water freeze faster?**

A: Wind chill does not lower the actual temperature of objects below the air temperature. Water will not freeze at 35°F regardless of wind chill. However, wind chill does mean that objects cool down to the air temperature faster because wind speeds up heat transfer.

**Q: How accurate is the wind chill formula?**

A: The 2001 NWS formula is based on controlled human trials and is considered much more accurate than the older Siple-Passel index. However, individual factors like clothing, body size, and physical activity affect how cold you actually feel.

**Q: Is wind chill different from heat index?**

A: Yes. Wind chill measures the combined effect of cold air and wind on heat loss. Heat index measures the combined effect of high temperature and humidity on heat gain. They apply to opposite ends of the temperature spectrum.

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Source: https://vastcalc.com/calculators/physics/wind-chill
Category: Physics
Last updated: 2026-04-08