Why Windchill Feels So Much Colder Than the Thermometer
Winter windchill depends heavily on wind speed, not just temperature. Stronger wind pulls heat from exposed skin faster, making conditions feel much colder than the actual reading — that's what windchill quantifies. This calculator applies the same windchill formula the US National Weather Service uses for winter advisories.
Enter temperature and wind speed to get the windchill value along with a five-level frostbite risk rating. Frostbite risk to exposed skin starts climbing once windchill drops below -13°F, and becomes very high with even short exposure below -49°F. Checking windchill before winter hiking, a commute, or outdoor work helps you decide what to wear or whether to adjust your schedule.
Because the formula is designed to capture wind-driven heat loss at cold temperatures, it doesn't produce a meaningful value above 50°F and is excluded from calculation in that range. It's most useful when a cold advisory is in effect or sub-freezing temperatures are expected.
Frequently Asked Questions
Stronger wind strips heat from exposed skin faster, making it feel much colder than the thermometer reading. This calculator uses the same windchill formula used by the US National Weather Service.
Frostbite risk to exposed skin starts rising once windchill drops below about -13°F, and becomes very high with short exposure once it drops below about -49°F.
The windchill formula was designed to capture heat loss from wind at cold temperatures. Above 50°F it no longer produces a meaningful value, so it's excluded from calculation.