Gardeners, beware of an early 'perfect frozen storm' | StarTribune.com

If it does freeze, it would happen more than three weeks earlier than the median freeze date of Oct. 7 at Minneapolis-St. Paul International Airport and more than two weeks ahead of Chaska's Oct. 2.
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[Mary Meyer, University of Minnesota professor and extension horticulturist] noted that the early cold coincides with a waning full moon, which she said can cast enough heat to clear the sky of clouds.

"This and the springtime are really the only times a full moon can give us a hard time," she said.