Dear Tom
Meteorologists seem to prefer dew point as a measure of moisture in the air during the warm months but seem to favor relative humidity in the cool months. Why?
William H. Russell, Chicago, Ill.
Dear William,
When it comes to the moisture content of air, the dew point temperature is the index of preference for most meteorologists, regardless of the time of the year. Relative humidity is used, but to a lesser extent in the atmospheric sciences. The National Weather Service calculates and releases hourly relative humidity values along with other hourly weather statistics because of public demand for that particular index. However, relative humidity gets special attention in the winter because it is a convenient and easily understood description of the dryness of indoor air in heated structures like houses.
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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.
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
