Wind Chill Calculator - Feels Like Temp
Calculate wind chill factor from air temperature and wind speed. Shows NWS wind chill equivalent temperature and frostbite risk time for cold weather
Formula
WC = 35.74 + 0.6215T - 35.75V^0.16 + 0.4275TV^0.16
The NWS Wind Chill formula uses air temperature (T in °F) and wind speed (V in mph) to calculate how cold it feels on exposed skin. Valid for temperatures at or below 50°F and wind speeds above 3 mph.
Worked Examples
Example 1: Moderate Winter Day
Problem: Temperature is 25°F with 15 mph winds. What is the wind chill?
Solution: Using NWS formula:\nWC = 35.74 + 0.6215(25) - 35.75(15^0.16) + 0.4275(25)(15^0.16)\nWC = 35.74 + 15.54 - 35.75(1.527) + 10.69(1.527)\nWC = 35.74 + 15.54 - 54.59 + 16.32\nWC = 13.0°F\n\nThe wind makes it feel 12°F colder than the actual temperature.
Result: Wind chill: 13°F (12° drop from actual)
Example 2: Dangerous Cold
Problem: Temperature is -10°F with 25 mph wind. Is it safe to be outside?
Solution: Wind Chill calculation:\nWC = 35.74 + 0.6215(-10) - 35.75(25^0.16) + 0.4275(-10)(25^0.16)\nWC = 35.74 - 6.22 - 57.18 - 6.84\nWC = -34.5°F\n\nAt -34.5°F wind chill:\n• Frostbite can occur in 10-30 minutes\n• All exposed skin must be covered\n• Limit time outdoors to essential activities
Result: Wind chill: -34.5°F - HIGH frostbite risk
Example 3: Exercise in Cold Weather
Problem: Planning a 30-minute run when it's 20°F with 10 mph wind. Safe?
Solution: Wind Chill: 35.74 + 0.6215(20) - 35.75(10^0.16) + 0.4275(20)(10^0.16)\n= 35.74 + 12.43 - 51.58 + 12.33 = 8.9°F\n\nRunning generates additional wind effect. At 6 mph running pace, effective wind = 16 mph.\nAdjusted wind chill ≈ 5°F\n\nFor 30-minute exercise at ~5°F effective:\n• Low frostbite risk if dressed properly\n• Cover face, ears, and hands\n• Wear moisture-wicking base layer\n• Safe for acclimated, healthy adults
Result: Generally safe with proper cold-weather gear
Frequently Asked Questions
What is wind chill and why does it matter?
Wind chill is the perceived temperature felt on exposed skin due to wind. Wind accelerates heat loss from your body, making it feel colder than the actual air temperature. A 30°F day with 20 mph wind feels like 17°F. Wind chill matters for safety - it determines how quickly you can get frostbite and hypothermia, not the actual temperature alone.
How is wind chill calculated?
The NWS Wind Chill Index uses: Wind Chill = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), where T is temperature in °F and V is wind speed in mph. This formula was updated in 2001 based on modern heat transfer science and human trials. It's valid for temperatures at or below 50°F and wind speeds above 3 mph.
Does wind chill affect objects like cars and pipes?
No. Wind chill only affects living things that generate heat. Objects cool to the ambient air temperature regardless of wind (wind just speeds up the cooling process). A car won't get colder than the air temperature. However, pipes can freeze faster in wind because they lose heat more quickly to reach air temperature.
What's the difference between wind chill and real feel temperature?
Wind chill only considers wind. 'Real feel' or 'apparent temperature' includes humidity, sun intensity, and wind. In summer, heat index adds humidity effects. Some services combine multiple factors. Wind chill is the official NWS measure for cold weather dangers and is standardized across all forecasts.
How should I dress for different wind chill levels?
Above 20°F: Normal winter layers, light hat/gloves. 10-20°F: Insulated jacket, warm hat covering ears, gloves, scarf. 0-10°F: Heavy coat, thermal underlayers, face protection. Below 0°F: Full coverage - exposed skin can freeze in minutes. Limit time outdoors. Below -20°F: Avoid outdoor exposure if possible.
Why does wind make it feel colder?
Your body constantly generates heat, warming a thin layer of air next to your skin. This insulating layer keeps you warm. Wind blows away this warm air and replaces it with cold air, accelerating heat loss. Faster wind = faster heat loss = lower perceived temperature. Proper clothing creates a barrier that the wind can't penetrate.