Wind Chill & Heat Index Feels-Like Calculator
Calculate official National Weather Service winter Wind Chill and summer Heat Index temperature, frostbite timelines, and heat stroke risk.
Calculated Results
Frequently Asked Questions
What is the National Weather Service (NWS) Wind Chill formula?
The official NWS formula (valid for temperatures ≤ 50°F and wind speeds > 3 MPH) is: Wind Chill (°F) = 35.74 + (0.6215 × T) - (35.75 × V^0.16) + (0.4275 × T × V^0.16), where T is air temperature in °F and V is wind speed in MPH.
What is the Heat Index formula?
The Heat Index combines ambient air temperature and relative humidity to measure how hot it feels to the human body. Because high humidity prevents sweat from evaporating, the body cannot cool itself efficiently, creating dangerous heat exhaustion and heat stroke conditions.
At what wind chill temperature does frostbite occur quickly?
At wind chills below -18°F, frostbite can occur on exposed skin in 30 minutes. At wind chills below -33°F, frostbite can occur in as little as 10 minutes.
Why does wind chill not affect inanimate objects?
Wind chill accelerates the rate of heat loss down to the ambient air temperature, but CANNOT cool an object below the actual air temperature. If it is 20°F with a wind chill of 0°F, water will freeze at 20°F, but never reach 0°F.