Wind Chill Calculator Widget

How it works

The wind chill temperature index adopted in 2001 by the US National Weather Service and the Meteorological Service of Canada models heat lost from a face walking into the wind. In Fahrenheit and mph the NWS formula is 35.74 + 0.6215T - 35.75V^0.16 + 0.4275TV^0.16; in Celsius and km/h the widget uses Environment Canada's version, 13.12 + 0.6215T - 11.37V^0.16 + 0.3965TV^0.16. Wind speed is the standard 10 m (33 ft) anemometer reading. The index is only defined at 50 °F (10 °C) or colder with wind of at least 3 mph, so the widget refuses inputs outside that range instead of extrapolating. Frostbite risk comes from Environment and Climate Change Canada's text table, keyed to the rounded wind chill in °C: -28 to -39 means exposed skin can freeze in 10-30 minutes, -40 to -47 in 5-10, -48 to -54 in 2-5 and -55 or colder in under 2. The NWS chart shades the same kind of 30, 10 and 5-minute zones but publishes them only as an image.

Calculation method

• US: WCT(°F) = 35.74 + 0.6215T - 35.75V^0.16 + 0.4275T x V^0.16, T in °F, V in mph
• Metric: WCT(°C) = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965T x V^0.16, T in °C, V in km/h
• Valid only for T <= 50 °F (10 °C) and V >= 3 mph (4.8 km/h); 1 mph = 1.609344 km/h
• Frostbite (ECCC, wind chill in °C rounded): -10 to -27 moderate; -28 to -39 freeze in 10-30 min; -40 to -47 in 5-10 min; -48 to -54 in 2-5 min; -55 or colder under 2 min

Worked examples

General cold-safety guidance based on weather-service tables, not medical advice. Follow local cold warnings.

Limitations

• Assumes a person walking into the wind at night with no sun; bright sunshine can make it feel noticeably warmer.
• Frostbite times are the ECCC table's ranges for typical adults; children, older people and anyone wet or with poor circulation are at higher risk.
• Not defined above 50 °F (10 °C) or for winds under 3 mph; Canada's separate light-wind formula is not used.

Where publishers use it

• Local weather and news sites during a cold snap or blizzard
• Ski resorts, snowmobile clubs and winter-hiking guides
• School districts explaining cold-weather closure and recess rules
• Construction, oil-field and delivery employers' cold-stress pages
• Dog-walking and outdoor-running blogs in northern climates

Questions

Sources

1. Understanding Wind Chill - US National Weather Service . Wind chill (°F) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16); 'only defined for temperatures at or below 50°F and wind speeds above 3 mph'. Checked 2026-10-01.
2. Wind Chill Temperature Index brochure - US National Weather Service . The chart's 30, 10 and 5-minute frostbite zones (shading only) and the 0 °F / 15 mph = -19 °F, frostbite in 30 minutes example.
3. Climate glossary - Wind chill - Environment and Climate Change Canada . Metric formula W = 13.12 + 0.6215 Tair - 11.37 V10m^0.16 + 0.3965 Tair V10m^0.16, wind at 10 m in km/h.
4. Wind chill and the Wind Chill Index - Government of Canada (Environment and Climate Change Canada) . Risk table by wind chill: -28 to -39 skin can freeze in 10-30 minutes, -40 to -47 in 5-10, -48 to -54 in 2-5, -55 or colder in under 2; faster in sustained winds over 50 km/h.

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A2Z Tools Wind Chill Calculator
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Wind Chill Calculator by A2Z Tools - https://a2z.tools/embed/wind-chill-calculator