September Climate Review

September 2013 featured the return of drought conditions over a large portion of central Illinois.  After the significantly wet first half of the year, dry weather began to take hold, especially from August into the first part of September.  An extended period of hot weather, during the second half of August into the first couple weeks of September, resulted in rapidly deteriorating soil moisture and crops.  By the end of September, severe drought conditions were observed from the Quad Cities southeast through Peoria and Bloomington to near Decatur (brown shades in lower right image).  Moderate drought was in areas from Springfield to Havana (tan shade in the lower right image).

Observed rainfall during the month (lower left image below) was highest west of the Illinois River, where amounts of 2.5 to 5 inches occurred from Galesburg to near Beardstown.  Most of this fell on the 7th, when totals included 4.30 inches at Prairie City, 3.5 inches at Knoxville, 2.84 inches at Galesburg, and 1.81 inches at Rushville.  The rainfall gradient was very tight on the eastern side of these storms, with no rain falling across northeast Knox County and less than 1/4 inch occurring northeast of Havana.  Most other locations in central and southeast Illinois averaged 1 to 2 inches during the month.  However, a persistent pocket of drier weather was observed from near Lincoln and Decatur east to Champaign, where amounts of less than an inch were common.  Decatur saw its 8th driest September on record with only 0.61 inches of rain, while the 0.93 inches at Lincoln was its 6th driest September on record.

Observed rainfall, September 2013

Drought Monitor from September 24th

Observed rainfall during September  
(Click image to enlarge)

Drought Monitor for Illinois as of September 24  
(Click image to enlarge)


Average temperature departure from normal during September.  Image courtesy of the Midwestern Regional Climate Center.

Temperatures started off the month in the 80s and 90s.  The hottest weather occurred from the 9th through the 11th.  On the 9th, highs approached 100 degrees along and west of the Illinois River.  On the 10th and 11th, these very hot temperatures were much more widespread, and highs in the upper 90s occurred as far east as I-57.  After that, much cooler conditions returned, with highs mainly in the 70s from the 13-17th, although a large area north of a Rushville to Bloomington line only saw highs in the mid to upper 60s on Sunday, September 16.  A warmer period also occurred from the 25-28th, with highs well into the 80s.

As a whole, temperatures averaged above normal during the month over central and southeast Illinois, especially from Champaign westward through the Illinois River valley.

The links below are the monthly climate summaries for area cities. Only the summaries for Peoria, Springfield and Lincoln are considered "official", meaning they are the station of record for their respective locations. The other summaries are "supplemental", meaning another location in the area is the official climate station for that city.

  • Peoria -- Peoria International Airport
  • Springfield -- Abraham Lincoln Capital Airport
  • Lincoln -- Lincoln NWS office
  • Champaign -- University of Illinois - Willard Airport
  • Decatur -- Decatur Airport
  • Lawrenceville -- Lawrenceville-Vincennes International Airport
  • Mattoon -- Coles County Airport

Climate data for other area cities is available at

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