Jun 26 | Climate Review and Weather Update
by Trent Ford, State Climatologist
ISWS PRI University of Illinois
We wrap up another week of wild weather in the prairie state. Average temperatures this week ranged from the mid-60s in northern Illinois to the mid-70s in southern Illinois, between 1 and 8 degrees below average. This week brought more beautiful evening and morning temperatures, and a few hours of chillier conditions including nighttime lows of 48 degrees in Rock Island and 52 in Champaign. The cooler weather mid-month combined with a warmer start to June has meant that month to date temperatures are right at the 30-year normal across the state, as are growing degree days stretching back to early May.
Once again, the week’s summary is dominated by discussion of another round of severe weather, this time unfortunately with fatalities. A series of storms moved through central and southern Illinois on Sunday, producing nearly 20 tornadoes in south-central and southeast Illinois, including an EF-3 in Jefferson County that claimed two lives. As of this morning, Illinois has had 173 tornadoes this year, smashing our previous record of 142 in 2024. The storms also brought substantially rainfall to central Illinois, with 7-day precipitation totals exceeding 3 inches across much of the I-74 corridor from the Quad Cities to Indiana. To date, this month has been the top 5 wettest on record in many places including Peoria, Bloomington-Normal, and Quincy. In fact, Gem City is already having its wettest start to the year since 2013 and the seventh wettest on record. Champaign-Urbana is only 2 inches away from its entire precipitation total from 2025.
Looking ahead, storms will move through the state this weekend but will mostly stay sub-severe. Unfortunately those storms will usher in some extreme heat, including multiple days with heat index values well over 100 degrees. This will be our first real taste of hazardous heat this summer, so please take precaution next week as you’re working outside. Farther out, the outlooks for the second week of July show a warmer and drier pattern in the Midwest. It looks like summer will visit us after all. Enjoy the July 4th holiday and stay weather aware.