Wind Chill Calculator
The 'feels like' temperature from air temp and wind speed (NWS formula).
Wind chill
6.2 °F
feels like (-14.3 °C)
Air temp
20 °F
Wind
15 mph
In Celsius
-14.3 °C
Formula valid?
Yes
AI Breakdown & Smart Takeaway
Plain-English insight on your numbers
Get a personalized explanation of what these results mean — and how to improve them.
How the Wind Chill Calculator works
The Wind Chill Calculator takes your current air temperature and wind speed and computes the 'feels like' temperature your body actually experiences, using the official National Weather Service (NWS) formula. It's an essential tool for anyone heading outdoors in cold, windy conditions — from hikers and runners to parents deciding whether kids need an extra layer.
Wind chill describes how quickly exposed human skin loses heat when cold air is moving across it. Still air acts as a thin insulating barrier around your body; wind strips that barrier away, accelerating heat loss and making the ambient temperature feel significantly colder than a thermometer reads. The faster the wind, the more efficiently it carries heat away from your skin, driving the 'feels like' temperature well below the actual air temperature. This physiological effect is what the Wind Chill Calculator quantifies in a single, actionable number.
The calculator uses the NWS wind chill formula adopted in 2001, which was developed from human clinical trials and replaced older, less accurate models. It applies only when the air temperature is at or below 50°F (10°C) and wind speed is at least 3 mph (about 5 km/h) — conditions under which wind chill is physically meaningful. Outside those thresholds, the 'feels like' temperature is essentially the same as the actual air temperature, so the formula is intentionally constrained to cold, windy scenarios where the risk of frostbite and hypothermia is real.
The two key inputs are air temperature and wind speed measured at 5 feet (standard walking height) rather than at anemometer height. A common mistake is plugging in wind speeds from an airport weather station, which are typically measured at 33 feet and will overstate the wind speed — and therefore overstate the chill — at ground level. Most consumer weather apps already correct for this, but it's worth knowing. Small changes in wind speed at low temperatures can produce dramatic shifts in the feels-like reading: a 10 mph wind at 0°F produces a wind chill of roughly -16°F, while a 30 mph wind at the same temperature drops it to around -26°F.
Understanding wind chill output helps you make smarter safety decisions. The NWS publishes frostbite timelines alongside wind chill values: exposed skin can freeze in 30 minutes at -18°F wind chill, in 10 minutes at -28°F, and in 5 minutes at -38°F or below. Use the calculator before outdoor activities to assess whether you need face protection, layering upgrades, or should simply shorten exposure time. Remember that wind chill does not affect inanimate objects like car engines or pipes — it is a human heat-loss metric only — so don't use it to predict whether water will freeze faster.
Formula
NWS: 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16 (T °F, V mph)
Pro tips
- Layer up before you hit the threshold: if the wind chill calculator shows -18°F or colder, cover all exposed skin — face mask, goggles, and insulated gloves are non-negotiable at that point.
- Use a local weather station's reported wind speed rather than airport data when possible, since airports often sit in open terrain that amplifies readings compared to suburban or forested areas where you'll actually be.
- Re-run the calculator when wind gusts are forecast: sustained wind and gust speed can differ by 15–20 mph, meaning the worst-case feels-like temperature is significantly colder than average conditions suggest.
- Factor in moisture: wet skin or damp clothing loses heat far faster than dry skin, so on days with snow, freezing rain, or high humidity, treat the wind chill output as a best-case estimate and dress one tier warmer.
- Set a time limit based on the frostbite timetable: if wind chill is between -18°F and -27°F, plan outdoor exposure in intervals of under 30 minutes with warm-up breaks indoors or in a heated vehicle.
Key terms
- Wind Chill
- — The perceived decrease in air temperature felt by the body due to the flow of cool air, expressed as an equivalent 'feels like' temperature.
- Feels Like Temperature
- — The human-perceived equivalent temperature that combines actual air temperature with the cooling effect of wind on exposed skin.
- NWS Formula
- — The National Weather Service wind chill equation adopted in November 2001, derived from human subject trials and validated against skin-cooling data.
- Frostbite Threshold
- — The wind chill temperature at which exposed human skin can begin to freeze, with the NWS warning level starting at approximately -18°F (-28°C) wind chill.
- Anemometer Height Correction
- — The adjustment made to convert wind speeds measured at standard 33-foot weather-station height down to 5-foot pedestrian height for accurate wind chill calculation.
- Hypothermia
- — A dangerous drop in core body temperature below 95°F (35°C), which wind chill accelerates by increasing the rate of heat loss from the body.
