How to use: Calculate wind chill (how cold it feels) when wind speed combines with air temperature. Enter Temperature and select unit (Fahrenheit or Celsius). Enter Wind Speed and select unit (mph, kph, or m/s). Results show "feels like" temperature accounting for wind. Wind chill only applies below 50°F (10°C) and above 3 mph wind. Formula uses NWS equation considering heat loss from exposed skin. Danger levels: Wind chill below 0°F = frostbite risk in 30 minutes, below -20°F = frostbite in 10 minutes, below -40°F = frostbite in 5 minutes. Higher wind speeds dramatically increase cold perception. Essential for winter safety, outdoor activity planning, and cold weather warnings.