Dear Tom,
I noticed that the moon was full for three straight nights at the end of July. How can it be full for so long?
Karen, Whiting, Ind.
Dear Karen,
Though the moon appeared to have been full for three consecutive nights, it actually was not. Technically there is a precise moment during each 29.5-day lunar cycle when 100% fullness is reached, and last month that moment occurred at 7:48 p.m. CDT on July 29. The night before on July 28 the moon was about 98% full and was called a waxing gibbous. On July 30, the night following the full moon, the lunar phase–though still about 99% full–was on the decline and called a waning gibbous. The next full moon occurs at 5:35 a.m. on Aug. 28, and on Sept. 26 the famed Harvest Moon reaches fullness at 2:45 p.m. Precise full moon times are available from the U.S. Naval Observatory as well as from various almanacs.
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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.
