Wind Chill Calculator · Practical guide
Wind Chill Chart with Frostbite Times
How cold it really feels — and how fast exposed skin can freeze — at each temperature and wind speed.
At a glance
Wind Chill and Frostbite Risk Chart
Frostbite risk is tied to the wind chill index, not the air temperature alone. The rule of thumb used by this calculator: at a wind chill of −19°F or below, exposed skin can freeze in about 30 minutes; at −36°F, about 10 minutes; at −55°F, about 5 minutes. Values are computed with the North American wind chill formula.
| Air temp | Wind speed | Wind chill | Frostbite risk |
|---|---|---|---|
| 40°F | 10 mph | 33.6°F | Low |
| 30°F | 20 mph | 17.4°F | Low |
| 20°F | 30 mph | 1.3°F | Low |
| 10°F | 25 mph | −10.7°F | Low |
| 0°F | 20 mph | −22.0°F | ~30 minutes |
| −10°F | 25 mph | −37.5°F | ~10 minutes |
| −20°F | 30 mph | −53.0°F | ~10 minutes |
| −30°F | 40 mph | −70.6°F | ~5 minutes |
Interactive tool
Wind Chill Calculator
Enter your own values, then compare the result with the examples below.
Wind Chill Results
How to Read the Chart
Notice the crossover: a calm 10°F day is manageable, but 10°F with 25 mph wind feels like −10.7°F. Wind chill drops steeply with the first increases in wind speed, then levels off — going from calm to 20 mph strips far more heat than going from 20 to 40 mph.
When the Chart Does Not Apply
The standard wind chill formula is only valid for air temperatures at or below 50°F (10°C) and wind speeds at or above 3 mph (5 km/h). Outside that range, wind chill is not a meaningful number — enter values in the calculator above and it will tell you if the formula does not apply.
Protecting Yourself
Wind chill only affects living tissue; it cannot make anything colder than the actual air. Fingers, toes, ears, and nose freeze first. In the 30-minute and 10-minute zones, cover all skin, layer loose dry clothing, and limit time outside. In the 5-minute zone, treat any exposed skin as an emergency waiting to happen.
Frequently Asked Questions
At what wind chill does frostbite start in 30 minutes?
At a wind chill index of about −19°F (−28°C) or colder, exposed skin can develop frostbite in roughly 30 minutes. Colder wind chills shorten that to 10 and then 5 minutes.
Is the frostbite time exact?
No — it is a guideline for healthy adults. Wet skin, direct metal contact, poor circulation, and individual susceptibility can all shorten the safe exposure time.
Why does wind chill level off at high wind speeds?
The formula raises wind speed to the 0.16 power, so each additional mph removes less heat than the one before. Most of the chilling effect happens by 20–25 mph.
Does the chart work in Celsius?
Yes. Switch the calculator to metric — the math converts °C and km/h through the same formula, and the frostbite thresholds (−28°C, −38°C, −48°C) match the Fahrenheit ones.