Wind chill is a measure that describes how cold it feels outside when the wind is factored in with the actual air temperature. When the wind blows, it removes heat from our bodies more quickly, making it feel colder than the thermometer indicates. This effect is especially noticeable in winter when temperatures drop and winds pick up. The wind chill index is calculated using both the air temperature and wind speed. For example, if the air temperature is 30°F and the wind is blowing at 20 mph, the wind chill can make it feel like 15°F. Understanding wind chill helps people dress appropriately and stay safe in cold weather conditions.