Dear Tom,
In Chicago what is the difference in daylight between the winter and summer solstices?
Zachary Weller Age 9 ,Chicago
Dear Zachary,
Your question is a timely one at the start of astronomical winter; a day when the sun’s most direct rays reach their southernmost position–the Tropic of Capricorn. In Chicago the amount of daylight received on the winter and summer solstices differs by about 6 hours and 5 minutes.
Daylight today will total 9 hours and 8 minutes as the sun travels low across the southern sky reaching a maximum angle of only 24.7(degrees) above the horizon. Compare that to the 15 hours and 13 minutes of daylight on the summer solstice when the sun reaches a maximum angle 71.6(degrees). In Chicago the intensity of sunlight as measured in langleys is nearly five times stronger in summer (506 langleys) than it is in winter (107 langleys).
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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.
