Wind Chill Calculator
A safety-first engine for navigating extreme winter conditions.
Wind Chill Calculator
When it's 25°F outside with a 20 mph wind, it doesn't feel like 25°F — it feels much colder. Wind chill is the "feels like" temperature that accounts for how wind strips heat from your body. This calculator tells you what to actually dress for.
What Is Wind Chill?
Wind chill is the perceived decrease in temperature caused by the flow of air. Moving air removes heat from exposed skin faster than still air at the same temperature. The wind chill temperature is not a true air temperature — it's a measure of how quickly your body loses heat.
How to Use This Calculator
- Enter the air temperature in °F or °C.
- Enter the wind speed in mph or km/h.
- Click Calculate to see the wind chill temperature.
Wind Chill Formula (NWS)
The current standard formula used by the US National Weather Service:
Wind Chill (°F) = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T × V^0.16
- T = Air temperature (°F)
- V = Wind speed (mph)
- Valid for temperatures ≤ 50°F and wind speeds ≥ 3 mph
Example Calculation
Temperature: 20°F, Wind speed: 15 mph
- Wind Chill = 35.74 + (0.6215 × 20) − (35.75 × 15^0.16) + (0.4275 × 20 × 15^0.16)
- ≈ 35.74 + 12.43 − 35.75 × 1.635 + 0.4275 × 20 × 1.635
- ≈ 35.74 + 12.43 − 58.45 + 13.98 = 3.7°F
It feels like 4°F even though the actual temperature is 20°F.
Frostbite Risk Chart
- Wind chill above 10°F → Low risk
- Wind chill −10°F to 10°F → Risk of frostbite in 30+ minutes
- Wind chill −10°F to −25°F → Risk of frostbite in 10–30 minutes
- Wind chill −25°F to −45°F → Risk of frostbite in 5–10 minutes
- Wind chill below −45°F → Risk of frostbite in under 5 minutes
Common Mistakes to Avoid
- Ignoring wind chill for clothing decisions — dress for the wind chill temperature, not the air temperature, when spending time outdoors.
- Assuming wind chill affects inanimate objects — wind chill only affects how quickly living skin loses heat. Your car's engine coolant, for example, won't freeze faster because of wind chill.
- Using wind chill above 50°F — the formula is only valid for temperatures at or below 50°F with sustained winds of 3+ mph.
Frequently Asked Questions
Does wind chill affect how quickly water freezes?
No. Wind chill only describes the heat loss rate from skin. A glass of water at 35°F will still freeze at 32°F regardless of wind speed.
What wind speed creates the most wind chill?
Wind chill effect increases rapidly up to about 40–50 mph, after which the incremental increase flattens out. Very high wind speeds don't dramatically increase wind chill beyond that threshold.
What is the difference between wind chill and heat index?
Wind chill measures cold-weather perceived temperature. The Heat Index measures the hot-weather equivalent — how hot it feels when humidity prevents sweat from evaporating efficiently.
When did the wind chill formula change?
The current NWS formula was adopted in 2001, based on research involving volunteer subjects in clinical trials to better reflect actual human heat loss.
Conclusion
Wind chill is the number that actually matters when you're deciding whether to add another layer, cover your face, or stay indoors. Use this calculator to plan outdoor activities safely in cold, windy conditions.
Related: Heat Index Calculator | Dew Point Calculator | Conversion Calculator
Winter Tip
If you are working outside, "Feels Like" is more important than "Actual Temp." Always dress for the wind chill, not the thermometer reading!
