What formula is used?

The current North American wind-chill index (2001): for imperial, 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16 with T in °F and V in mph; the metric version uses T in °C and V in km/h with the matching coefficients.

Why is there a valid range?

The index was fitted for cold, windy conditions — temperatures at or below 10 °C (50 °F) and winds above 4.8 km/h (3 mph). Outside that range the number is shown but flagged, since it is not meaningful.

Is wind chill the same as 'real feel' or heat index?

No. Wind chill applies to cold weather and only depends on temperature and wind. Heat index applies to hot weather and depends on temperature and humidity instead.

Is my data sent anywhere?

No. The calculation runs entirely in your browser; nothing is uploaded.

Wind Chill Calculator (°C and °F)

Wind chill describes how cold the air feels on exposed skin once moving air carries body heat away faster than still air would. This calculator uses the official NWS (imperial) and Environment Canada (metric) wind-chill formulas, taking the air temperature and wind speed and returning the 'feels like' temperature plus how many degrees colder it feels. The formulas are defined for temperatures at or below 10 °C (50 °F) and wind above 4.8 km/h (3 mph); outside that range a note is shown. Everything runs locally in your browser — nothing is uploaded.

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Units

Air temperature (°C)Wind speed (km/h)

Wind chill (feels like)-13 °CFeels about 8 °C colder than the air temperature.

How to use

Choose metric (°C, km/h) or imperial (°F, mph).
Enter the air temperature and the wind speed.
Read the wind chill — the 'feels like' temperature — and how much colder it feels.

Frequently asked questions

What formula is used?: The current North American wind-chill index (2001): for imperial, 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16 with T in °F and V in mph; the metric version uses T in °C and V in km/h with the matching coefficients.
Why is there a valid range?: The index was fitted for cold, windy conditions — temperatures at or below 10 °C (50 °F) and winds above 4.8 km/h (3 mph). Outside that range the number is shown but flagged, since it is not meaningful.
Is wind chill the same as 'real feel' or heat index?: No. Wind chill applies to cold weather and only depends on temperature and wind. Heat index applies to hot weather and depends on temperature and humidity instead.
Is my data sent anywhere?: No. The calculation runs entirely in your browser; nothing is uploaded.

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