An arctic outbreak in late January led to widespread bitterly cold temperatures across much of the Upper Midwest, including Illinois. On the morning of Jan. 31, the cooperative weather observer at Mount Carroll in Carroll County reported a temperature of -38 degrees.
After a comprehensive review, the State Climate Extremes Committee unanimously voted to validate the reading as the new official state record minimum temperature. This committee ensures that the observation is meteorologically plausible, is within a range that the reporting instrument can detect and that the instrument is in proper working order.
Brian Kerschner at the Illinois State Water Survey, part of the Prairie Research Institute at Illinois, represented the Illinois State Climatologist Office as a member of the SCEC, along with delegates from the National Weather Service, the Midwest Regional Climate Center and the National Center for Environment Information.
The previous minimum temperature record for Illinois was -36 degrees set in Congerville, located in Woodford County, on Jan. 5, 1999. The coldest temperature prior to the Congerville record, -35 degrees, was also set at Mount Carroll in January 1930.
The Mount Carroll station is a traditional daily observing station located in northwestern Illinois. It has been in service, with minor interruptions, since 1895, and has been observing temperatures since 1897. It is operated by the City of Mount Carroll and attended by staff at the city’s water treatment plant.
The final report is on the NCEI websiteas well as a complete list of current state records.
