Weather Active July In The Books

After a drier than normal June, Hurricane Beryl and an active, stormy July resulted in statewide precipitation of 7.01 inches, 2.95 inches above the 1991-2020 average and the third wettest on record, according to Illinois State Climatologist Trent Ford at the University of Illinois’ Illinois State Water Survey.
Total preliminary July precipitation ranged from around 4 inches in parts of northeast Illinois to more than 12 inches in south-central Illinois, between 1 and 7 inches above normal. Several spots in the St. Louis Metro East area picked up more than 13 inches of rain in July, including an incredible 16 inches in Mascoutah.
The remnants of Hurricane Beryl, one of the strongest early season Atlantic hurricanes on record, bent up through the Midwest, producing significant rainfall over a 48-hour period across parts of central and east-central Illinois. Parts of Champaign and Douglas counties picked up more than 4 inches in two days from, dramatically improving soil moisture and streamflow.
Less than a week later, an intense storm system moved across the northern half of the state, producing very heavy rainfall and a derecho that brought severe straight-line winds. Most of the state picked up at least 1 inch of rain over the 48-hour period between July 14 and 16, and multiple areas received more than 6 inches, including just over 8 inches in Fulton County. Heavy rain in St. Clair and Washington counties caused significant flooding and forced the opening of a dam spillway near Nashville.
The same storm system on July 15 produced dozens of tornadoes across Illinois, including more than 30 in the Chicago National Weather Service county warning area. It was the largest single-day tornado outbreak on record for the Chicago area.
As of July 31, Illinois had an unofficial total of 126 in 2024, according to the National Weather Service. This is a preliminary total and may be adjusted later this year as reports are refined. The current official annual tornado record for Illinois is 124 in 2006.
July offered a mixed bag of temperatures, but more days last month were cooler than normal. While last month also brought some intense heat, it was fleeting. Overall, the preliminary statewide average July temperature was 73.8 degrees, 1.6 degrees below the 1991-2020 average and tied for 29th warmest on record going back to 1895. This was also the second consecutive July with a statewide average temperature below normal, the first time we have had back-to-back cooler than normal Julys since 2014-15.
Outlooks
August is the beginning of the end of summer but can certainly bring its fair share of heat. August is also an important month for finishing crops as fall approaches. The most recent Climate Prediction Center outlooks for August show equal chances of above and below normal temperatures in northern Illinois and higher chances of above normal temperatures in southern and central Illinois. August precipitation outlooks are leaning wetter than normal in northern Illinois and near normal for central and southern Illinois.
The newest climatological fall — September through November — outlooks show slightly higher chances of above normal temperatures, with equal chances of a drier or wetter than normal fall.