Wind chill at 20°F and 30 mph
Here’s the wind chill for 20°F air temperature with a 30 mph wind.
Different temperature or wind speed? Use the full wind chill calculator above.
About the wind chill calculator
Wind chill describes how much colder moving air makes exposed skin feel compared to the actual air temperature, because wind strips away the thin layer of warm air your body naturally holds against your skin. This calculator uses the official US National Weather Service wind chill formula, adopted in 2001, which replaced an older formula from the 1970s that overestimated the cooling effect of wind.
The exact formula is: wind chill (°F) = 35.74 + 0.6215T − 35.75(V^0.16) + 0.4275T(V^0.16), where T is the air temperature in degrees Fahrenheit and V is the wind speed in miles per hour. The V^0.16 term reflects research on how heat loss from human skin actually scales with wind speed — it's not a linear relationship, which is why the formula uses that specific exponent rather than a simple multiplier.
This formula is only meteorologically valid under the conditions it was derived for: air temperature at or below 50°F and wind speed at or above 3 mph. Below 3 mph there's not enough consistent airflow for the wind chill effect to apply in any meaningful way, and above 50°F the cooling effect of wind on skin becomes negligible to the point that the formula's assumptions no longer hold.
This calculator still computes a numeric result outside that range — say, at 65°F with a 2 mph breeze — because the underlying math will always produce a number, but it displays a clear note when your inputs fall outside the formula's intended conditions. Treat any result shown under that note as not meteorologically meaningful, since real wind chill only matters when it's genuinely cold.
Wind chill only measures the perceived cooling from moving air on exposed, dry skin — it doesn't account for humidity, sunshine, or wet skin and clothing, all of which can meaningfully change how cold a given temperature and wind speed actually feel. It's a useful safety indicator for frostbite and hypothermia risk in cold, windy conditions, not a complete measure of how comfortable you'll feel outside.
Wind chill calculator questions
How the National Weather Service wind chill formula works.
What is the wind chill formula?
The US National Weather Service wind chill formula is: 35.74 + 0.6215T − 35.75(V^0.16) + 0.4275T(V^0.16), where T is air temperature in Fahrenheit and V is wind speed in mph.
How do you calculate wind chill?
Plug your air temperature (in °F) and wind speed (in mph) into the National Weather Service formula. This calculator does the math automatically — just enter both values and read the result.
Is the wind chill formula valid at any temperature?
No. The formula is only meteorologically valid for air temperatures at or below 50°F and wind speeds at or above 3 mph. Outside that range, the cooling effect of wind on skin is too small to reliably model, so any result should be treated as informational only.
Why does wind chill matter?
Wind chill estimates how quickly exposed skin loses heat in cold, windy conditions, which is a useful indicator of frostbite and hypothermia risk. A lower wind chill value means faster heat loss and greater risk from prolonged exposure.
What's the difference between air temperature and wind chill?
Air temperature is what a thermometer reads. Wind chill is how much colder the wind makes bare skin feel, since moving air pulls away the warm layer of air your body holds close to your skin faster than still air does.
What is the wind chill at 20°F with 15 mph wind?
At 20°F with a 15 mph wind, the wind chill is about 6°F, meaning exposed skin loses heat as if the air were around 6°F even though the thermometer reads 20°F.