What is the windchill temperature?
The windchill describes the increased loss of heat by the movement of the air.
The windchill is relevant to humans and other animals that need to maintain a constant temperature that is higher than their surroundings.
The windchill cannot be measured with a thermometer; it must be computed.
The windchill temperature index, expressed in degrees, translates your body’s heat losses under the current temperature and wind conditions into the air temperature with a 3 mph wind that would produce equivalent heat losses.
The original windchill formula, devised by Antarctic explorer Paul Siple in 1945, was based on research involving the time it took water in a plastic container to freeze.
The National Weather Service updated the formula in November 2001.
This modern-day windchill temperature index takes into account a calculated wind speed based at the average height of a human face (not at the winds measured at the national standard height of 33 feet), the exposure of a human face to cold vs. a plastic container, incorporates heat transfer theory, lowers the calm wind threshold from 4 mph to 3 mph, and has a consistent standard for skin tissue resistance.
As an example, a temperature of 0 degrees and a wind of 30 mph has a windchill temperature index of -26.
If left outside, an object will never reach a temperature of -26, it will cool down to 20 at a cooling rate equivalent to an outside temperature of -26 and a wind at 3 mph.
Under these conditions, frostbite would occur within 30 minutes.
Frostbite occurs when your skin and other tissues cool down to the point that ice crystals form in your bodily fluids.
Cold temperatures combined with strong winds can cause frostbite in a matter of minutes, and the windchill temperature index is used to determine cold hazardous conditions.
