Dear Tom,
We are studying weather and I want to ask you how many days in a year we have precipitation. How many days do we have heavy precipitation?
— Robert, Wilmette
Dear Robert,
The Chicago area receives precipitation (rain, snow, drizzle and sleet) quite often. That comes as no surprise, considering that far above-normal precipitation has been drenching us since summer. In 138 years (1871 through 2008, or 50,404 days), measurable precipitation (0.01 inch or more) has fallen on 17,153 days, or an average of 124 days per year. In addition, a trace of precipitation (like a few drops of rain or a few flakes of snow) has fallen on 8,292 days, or 60 days per year. On average, at least some precipitation (trace or measurable) falls on 184 days, or about half of the year.
Heavy precipitation (1 inch or more) arrives seven days per year.
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Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or: asktomwhy@wgntv.com
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