Dear Tom,
When looking at weather maps, I sometimes see days with very little precipitation anywhere in the country, but always some. Has there ever been a day when there was no precipitation of any kind in the entire country?
Jan Paull, Naperville
Dear Jan,
It is highly unlikely. On rare occasions there may be a few precipitation-free hours across the 48 states, but certainly not through an entire 24-hour period. Because of its great size, at least one precipitation-generating weather system is almost always present somewhere in the United States. But even lacking that, a few afternoon thunderstorms are a certainty across the mountainous terrain of the West during the warm season, and lake-effect snow (or rain) is usually present somewhere in the Great Lakes region in the cold season.
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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.
