Wind chill is the "feels-like" temperature on exposed skin when cold air combines with wind. A calm -5°C day feels very different from a windy -5°C day, and this calculator uses the official U.S. National Weather Service formula to tell you exactly how cold it feels — and how quickly frostbite could set in.
The formula is valid for temperatures at or below 10°C (50°F) and wind above about 4.8 km/h (3 mph). Outside that range the tool shows a note, because the wind chill effect is negligible or undefined in warm, still air.
Does wind chill change the actual temperature? No. It only describes how cold it feels on skin; water does not freeze above 0°C even if the wind chill is below zero.
Why is there no result when it is warm? The formula only applies below 10°C (50°F), so the tool flags warm readings instead of giving a misleading number.
Is my data private? Yes. All calculations run in your browser.