Put very simply, wind chill is the measure of how quickly a person or animal becomes susceptible to frostbite or hypothermia. Gusts of wind will strip heat away from the body, making it feel much colder than the air temperature. For example, on a 5° day with wind gusts of 30 miles per hour, it will feel as though it is -19° and frostbite can set in, in as little as thirty minutes. Wind chill does not impact bodies of water, or anything that does not produce its own heat.