Chicago, IL – September 2025 closed out as one of the driest on record for northern Illinois, with both Chicago and Rockford experiencing well below-average rainfall and above-normal temperatures.
According to the National Weather Service Chicago office, Chicago’s O’Hare International Airport recorded an average temperature of 69.3 degrees, which is 3.0 degrees above normal. The city saw only 0.49 inches of rain, making it the 7th driest September on record with rainfall nearly 3 inches below normal.
In Rockford, conditions were similar. The city’s average temperature was 66.5 degrees, about 2.1 degrees above normal. Rainfall totaled just 1.05 inches, which is 2.57 inches below normal.
Maps released by the National Weather Service show much of northern Illinois in the red zone for precipitation deficits, with many counties receiving less than 50 percent of typical September rainfall. The agency noted that the region was dominated by warmer and drier-than-usual weather patterns throughout the month.
These conditions have implications for agriculture, water resources, and fall wildfire risk, as dry soil and vegetation increase vulnerability to fire spread. The National Weather Service will continue to monitor precipitation trends into October as the fall season advances.
