Weather
Chicago, Rockford End Warm, Wet September
Chicago, IL – September finished warmer and wetter than normal in both Chicago and Rockford, with Chicago tying its 10th warmest September on record.
By Lena Wood · 2026-10-01T18:11:36.839Z
Chicago, IL – September finished warmer and wetter than normal in both Chicago and Rockford, with Chicago tying its 10th warmest September on record.
According to the National Weather Service in Chicago, Chicago’s average temperature for September was 70.1 degrees, 3.8 degrees above normal. The average high was 77.3 degrees, or 1.8 degrees above normal, while the average low of 63.0 degrees was 5.9 degrees above normal.
Chicago O’Hare recorded 3.70 inches of precipitation during the month, 0.51 inches above normal.
Several daily temperature records were also reached in Chicago early in September. A low of 78 degrees on Sept. 2 tied the record for the warmest daily low, while lows of 77 degrees Sept. 3 and 76 degrees Sept. 4 set daily warm low records.
The monthly average of 70.1 degrees tied for the 10th warmest September in Chicago’s temperature record, which dates to 1872.
Rockford also had a warmer and substantially wetter September. The city averaged 68.0 degrees for the month, 3.6 degrees above normal. Its average high was 77.6 degrees, 2.3 degrees above normal, while the average low of 58.4 degrees was 4.9 degrees above normal.
Rockford recorded 7.40 inches of precipitation, 3.78 inches above normal. A daily rainfall record of 2.63 inches was set Sept. 19. The city also tied a warm low record of 73 degrees Sept. 3 and set a warm low record of 73 degrees Sept. 4.
No top 10 monthly records were set at Rockford, where climate records date to 1905.
The NWS report is a retrospective September summary and does not provide an October forecast; current conditions and upcoming weather will depend on separate NWS forecasts and outlooks.