Weather in Rockford, Illinois for September 2026
Flood Watch - See hour by hour.
So far, September 2026 in Rockford is slightly warmer than the historical average by 1.5 °F.
Expect cooler weather in the next days in Rockford with the forecast suggesting a temperature of 17.1 °F, lower than the historical average.
In general, the average temperature in Rockford at the beginning of September is 28.1 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 19 °F by the end of September.
The climate of Rockford in September is notably wet, with an average of 11 rainy days, and a total of 72.2 mm of precipitation.
New! Chat with our AI weatherman - it’s amazing and free.
Official Weather Alert ⚠️
Temperatures
Rain 🌧️
More
Rockford Weather September
Temperatures trend during September in Rockford
September weather in Rockford day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /12° | 0 mm | 7 | |
| Sept. 2 | Sunny | 30° /13° | 0 mm | 7 | |
| Sept. 3 |  Partly cloudy | 31° /14° | 8.6 mm | 7 | |
| Sept. 4 |  Cloudy | 30° /14° | 0 mm | 6 | |
| Sept. 5 |  Overcast | 29° /16° | 0.8 mm | 6 | |
| Sept. 6 |  Patchy rain possible | 25° /11° | 1 mm | 5 | |
| Sept. 7 | Patchy rain possible | 23° /8° | 0.1 mm | 5 | |
| Sept. 8 |  Mist | 25° /9° | 0 mm | 5 | |
| Sept. 9 | Mist | 27° /11° | 16.9 mm | 5 | |
| Sept. 10 | Fog | 28° /12° | 0 mm | 6 | |
| Sept. 11 | Light rain shower | 26° /13° | 3.5 mm | 6 | |
| Sept. 12 | Fog | 27° /13° | 0 mm | 6 | |
| Sept. 13 | Mist | 26° /14° | 0.6 mm | 6 | |
| Sept. 14 | Mist | 27° /11° | 0 mm | 6 | |
| Sept. 15 | Mist | 29° /14° | 5.8 mm | 6 | |
| Sept. 16 | Light rain shower | 28° /14° | 1.3 mm | 5 | |
| Sept. 17 | Sunny | 26° /12° | 9.8 mm | 5 | |
| Sept. 18 | Mist | 26° /11° | 0.6 mm | 6 | |
| Sept. 19 |  Moderate or heavy rain with thunder | 26° /13° | 26.5 mm | 5 | |
| Sept. 20 | Light rain shower | 20° /14° | 57.9 mm | 0.7 | |
| Sept. 21 | Overcast | 15° /12° | 0.6 mm | 1 | |
| Sept. 22 | Patchy rain possible | 16° /10° | 0.7 mm | 5.3 | |
| Sept. 23 | Sunny | 18° /10° | 0.2 mm | 5.2 | |
| Sept. 24 | Overcast | 19° /11° | 0 mm | 5.1 | |
| Sept. 25 | Overcast | 18° /13° | 0 mm | 4 | |
| Sept. 26 | Overcast | 15° /14° | 0 mm | 3 | |
| Sept. 27 | Sunny | 21° /14° | 0 mm | 6 | |
| Sept. 28 | Sunny | 21° /13° | 0 mm | 6 | |
| Sept. 29 | Overcast | 21° /12° | 0 mm | 5 | |
| Sept. 30 | Patchy rain possible | 18° /11° | 4 mm | 4 | |
| Next | |||||
Rockford in September - FAQ
What are the expected maximum and minimum temperatures in Rockford during September?
How much rainfall should be expected in Rockford during September?
What are the typical wind conditions in Rockford during September?
September rainfall patterns in Rockford
UV exposure in Rockford during September
Quick links
Where is Rockford?Get accurate weather forecasts for Rockford, located at latitude 42.271 and longitude -89.094. Stay updated with localized weather information tailored for Rockford.