Coldest July on Record for the Midwest 2009

This was the coldest July on record for the nine-state Midwest region, based on preliminary temperature data. The average temperature for the region was 68.0 degrees, 4.7 degrees below normal. The previous record was 68.9 degrees in 1992, according to Mike Timlin, Regional Climatologist with the NOAA Midwestern Regional Climate Center (https://mrcc.isws.illinois.edu).

It was the coldest July on record for Indiana, Illinois, and Iowa; the second coldest on record for Michigan, Kentucky, Ohio, and Wisconsin; the third coldest in Minnesota; and the fourth coldest on record for Missouri. Records for the region date back 114 years.

Timlin says that more than 400 record low minimum temperatures and 1,300 record low maximum temperatures (lowest high temperature) were set during July across the nine-state region.

“Temperatures were below normal for most of July with two particularly cold periods. The first was July 1-9, and the second was July 17-23,” states Timlin.

There were 370 record low maximum temperatures set during the period July 1-9, and 23 record low minimum temperatures. Temperatures ranged from 2 degrees below normal in southern Missouri to as much as 8 degrees below normal in the Michigan Upper Peninsula.

During the period from July 17 to 23, temperatures were 10 to 12 degrees below normal across Iowa, Missouri, much of Illinois, southern Indiana, and western Kentucky, and 6 to 9 degrees below normal across the remainder of the region. A total of 942 record low maximum temperatures and 337 record low minimum temperatures were established over this seven-day period.

Many locations in the central Midwest did not reach 90 degrees at all during the month. Typically, the number of days with temperatures reaching 90 degrees or above ranges from 10 to 15 from southern Missouri eastward through Kentucky, and three to five in the northern third of the region.

Louisville, KY normally has about 12 days of temperatures 90 degrees or above in July, and recorded none this July. St. Louis, MO normally experiences 16 days with temperatures 90 degrees or above, and recorded only four in July.

International Falls, MN did not report a single day 80 degrees or higher, and experienced its coldest July on record with an average temperature of 58.8 degrees, breaking the old record of 59.4 degrees set in 1992.

Other locations in the Midwest that had a record cold July include:

* Madison, WI - average temperature of 65.7 degrees, old record 66.7 degrees in 1891
* Grand Rapids, MI – average temperature 67.1 degrees, old record 67.2 degrees in 1992
* Cedar Rapids, IA – average temperature 66.2 degrees, old record 69.9 degrees in 2004
* Rockford, IL – average temperature 67.0 degrees, old record 69.0 degrees in 1915
* South Bend, IN – average temperature 68.3 degrees, old record 68.5 degrees in 1996
* Cincinnati, OH – average temperature 70.1 degrees, old record 70.7 degrees in 1947
* Frankfort, KY – average temperature 71.5 degrees, old record 75.2 degrees in 1947

In Missouri, Columbia recorded its second coldest July on record with an average temperature of 72.3 degrees. The record is 72.2 degrees in 1924.

July precipitation was normal to above normal from southwestern Minnesota to southern Ohio and eastern Kentucky. Rainfall was less than 50 percent of normal from south-central Minnesota across much of Wisconsin. Parts of central Minnesota, much of the northern half of Wisconsin, and the western half of the Michigan Upper Peninsula remained in moderate to severe drought at the end of the month, according to the U.S. Drought Monitor.

The Midwestern Regional Climate Center is a program funded by the National Oceanic and Atmospheric Administration, and is located in the Division of Illinois State Water Survey in the Institute of Natural Resource Sustainability at the University of Illinois at Urbana-Champaign.