wind chill


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Related to wind chill: Wind chill factor

wind chill,

the cooling effect of wind and temperature combined, expressed in terms of the effect produced by a lower, windless temperature, also called wind chill factor, wind chill temperature, wind chill equivalent temperature, wind chill index, wind chill equivalent index, and wind chill temperature index. Wind chill is based on the rate of heat loss from exposed skin. Under windless conditions air provides an invisible blanket around the skin. As wind speed increases, this layer of heated air is carried away from the body at an accelerated rate, forcing the body either to work harder to generate more heat or cool down. If the actual air temperature is −5°F;(−21°C;) with a 20 mph (32 km/hr) wind, the wind chill temperature is −29°F;(−34°C;). Because wind chill is based the removal of heat from the human body, it does not reflect the increased rate of heat loss for inanimate objects such as automobile radiators under the same conditions but they also experience a faster heat loss with increasing winds.

The term wind chill was coined by the American geographer Paul A. Siple in his dissertation, Adaptation of the Explorer to the Climate of Antarctica, (1939). Subsequently, on the third Byrd Antarctic expedition, Siple and American geologist Charles Passel determined how quickly extreme conditions could produce frostbite on exposed skin. By 1945, Siple and Passel had published a set of numbers expressing heat loss as a function of temperature and wind speed.

A wind chill advisory is issued when the forecast projects a wind velocity of at least 10 mph (16 km/hr) producing a wind chill temperature of −15°F; or lower for 3 hours or more. At these values wind chill is more of a nuisance than it is life threatening. A wind chill warning is issued when the forecasted wind chill temperature is −25°F; or lower, which can be life threatening if the individual is not suitably dressed. Persons who go outside under such conditions may experience frostbite and other cold-related symptoms in a matter of minutes, even if properly clothed for normal winter conditions, and longer exposures may prove fatal.

wind chill

[′win ‚chil]
(meteorology)
That part of the total cooling of a body caused by air motion.
References in periodicals archive ?
Generally, we count wind chill factor for the temperatures lower than 10 degrees Celsius and winds with speeds of 4.8 kmph or more," said a senior IMD official.
Widespread wind chill warnings and advisories were issued from eastern Montana and Wyoming through Minneapolis, Chicago and St.
In other words, the common effect of wind and temperature in loss of heat in human body and other organisms is called wind's chill-producing or wind chill [2].
Rescuers had to contend with "horrendous" conditions and a wind chill of -250C.
The group was found near the peak in temperatures of minus five degrees and wind chill of minus 19.
"We are forecast plus two or three overnight but it is the wind chill that could cause problems."
Sun exposure (northern versus southern), altitude, wind, and wind chill factors can change the average temperature and first frost date in any zone.
'As well as keeping out the wind chill, it also wipes sweat away from the skin.'
At race time, the temperature was 4 with a wind chill of 7 below zero.
Arguably, the most popular guideline is wind chill. In November 2001, the National Weather Service (NWS) changed the wind chill temperature index, and the latest formula is used extensively throughout Canada and the United States (see wind chill chart, page 21).
Planting reduces the wind chill and evaporative heat loss from the pool.
Cherry originally had planned to walk home, but decided to catch a ride after work because of the wind chill.