Dear Tom,
Ice fishermen tell me a below-freezing wind chill helps freeze ice even when the temperature is above freezing. I do not believe this is true.
Chuck Leoni, Wauconda
Dear Chuck,
You are correct. The wind chill is a measure of how cold the air feels on exposed skin based on a combination of temperature and wind speed. In effect, it implies a rate of heat loss. No matter how low the wind chill is reported, the laws of physics apply: Water will not freeze if the ambient temperature is above freezing.
However, if the temperature sinks below freezing, a cold wind chill will hasten ice formation since it the increases the rate of heat loss. The same applies for starting automobiles in cold weather. No matter how cold the wind chill, an auto’s starting ability is based on the temperature, not the wind chill. After you turn off the engine, the wind chill determines how quickly the car will cool down.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
