Illinois State Water Survey Illinois State Climatologist

Contrails and Cloudiness

This morning we had a brilliant display of airplane contrails, enough to significantly increase the cloudiness (as if we needed more cloudiness this winter). Despite rumors to the contrary, airplane contrails are just the byproducts of burning jet fuel at high altitudes where the air is very cold and dry. The basic chemistry involves combing a […]

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January through October – 6th coolest and 19th wettest for Illinois

For the period from January through October, the statewide temperature for Illinois was 52.5 degrees, a full 3 degrees below the long-term average of 1981-2010 and the sixth coolest year to date on record with those records going back to 1895.  The five colder years were 1904, 1917, 1979, 1912, and 1978. Of course, you […]

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Wetter Averages and Extremes for Chicago Area

The recent rains and associated flooding in the Chicago area are reflecting the long-term pattern of wetter conditions in the region. Here are a few samples of that pattern. First of all, northeast Illinois (Cook and several surrounding counties – see map below) has experienced a shift in precipitation over the last 120 years. This […]

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All Quiet on the Severe Weather Front

As of May 8, 2013, the severe weather statistics for Illinois this year are relatively low (see first map). There have been 2 tornado reports (red dots), 25 hail reports (green dots), and 62 wind damage reports (blue dots). By this point last year, we had 22 tornadoes including the deadly February 29 tornado at […]

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