Wind chill calculator
What the wind chill means
The National Weather Service describes the wind chill as how cold people and animals feel when they are outside. It is based on how fast exposed skin loses heat to wind and cold. The stronger the wind, the faster that heat goes, and the colder it feels.
These four bands are our own simple summary. Only the -19°F line comes from the National Weather Service. Since October 1, 2024 the NWS uses the names Cold Weather Advisory and Extreme Cold Warning for these alerts. Your local NWS office decides when to issue them, and the criteria differ per region.
Wind chill at a glance
The same formula as the calculator, for common combinations (°F). Read down a column to see what extra wind does to the same temperature.
| Wind \ Temp | 40°F | 30°F | 20°F | 10°F | 0°F | -10°F | -20°F | -30°F |
|---|---|---|---|---|---|---|---|---|
| 5 mph | 36 | 25 | 13 | 1 | -11 | -22 | -34 | -46 |
| 10 mph | 34 | 21 | 9 | -4 | -16 | -28 | -41 | -53 |
| 15 mph | 32 | 19 | 6 | -7 | -19 | -32 | -45 | -58 |
| 20 mph | 30 | 17 | 4 | -9 | -22 | -35 | -48 | -61 |
| 30 mph | 28 | 15 | 1 | -12 | -26 | -39 | -53 | -67 |
| 40 mph | 27 | 13 | -1 | -15 | -29 | -43 | -57 | -71 |
Calculated with the NWS wind chill formula. These values match the National Weather Service wind chill chart.
Can wind chill freeze water, pipes or your car?
No. This is the most common wind chill mix-up. The National Weather Service says wind chill only applies to people and animals. For objects such as car radiators and water pipes, the only effect is that they cool down faster. They never get colder than the actual air temperature.
Air -5°F, wind chill -31°F
Your car's radiator will not drop below -5°F. The wind just gets it there sooner.
Freezes at 32°F
What decides whether water freezes is the real air temperature, not the wind chill. On a 36°F day with a 30 mph wind the wind chill is about 23°F, but your garden hose does not freeze.
Wind dries, it does not chill
Wind chill does not apply to plants either. In winter, wind can dry out evergreens when the ground is frozen, which UNH Extension calls winter burn.
Want the full explanation, with pipes, plants and pets? Read wind chill explained: can it freeze water, pipes or plants?
How the calculator works
We use the National Weather Service Wind Chill Temperature Index: Wind chill (°F) = 35.74 + 0.6215T - 35.75(V0.16) + 0.4275T(V0.16), where T is the air temperature in °F and V the wind speed in mph. The NWS defines it only for temperatures at or below 50°F and wind speeds above 3 mph, so the calculator does the same. Celsius and km/h are converted to °F and mph first.
Quick answers
Why does the calculator stop above 50°F?
The National Weather Service defines the wind chill only at or below 50°F. On a mild day a breeze feels nice, but the formula is not made for it.
Which wind speed should I use?
The sustained wind from your forecast or weather station, not the highest gust. Our page on how to measure wind speed explains averages and gusts.
Does wind chill affect my dog?
Yes. The NWS says wind chill applies to people and animals. Bring pets inside or give them a sheltered, warm place when it is very cold and windy.
What is the difference with "feels like"?
Many apps show one "feels like" number: in winter that is usually the wind chill, in summer the heat index. For hot weather, use our heat index calculator.
Sources: National Weather Service: Wind Chill Chart · National Weather Service: Cold FAQs · UNH Extension: Winter Burn on Evergreens · NWS: Cold hazard simplification
