Winnebago County (Rockford)
September
Weather in Winnebago County, Illinois for September 2026
Your guide to Winnebago County weather in September - trends and predictions
In general, the average temperature in Winnebago County at the beginning of September is 25.9 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 24.7 °F by the end of September.
The climate of Winnebago County in September is notably wet, with an average of 11 rainy days, and a total of 62.6 mm of precipitation.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
19
Dry days
11
Rainy days
0
Snow days
26°/12°
Temperatures
18 km/h
Avg max wind
67 %
Avg humidity
Winnebago County Weather September
Move between months or click on a day
Temperatures trend during September in Winnebago County
See the weather trend as well as the moving average line
September weather in Winnebago County day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 26° /10° | 0 mm | 6 | |
| Sept. 2 |  Mist | 28° /10° | 0 mm | 6 | |
| Sept. 3 |  Partly cloudy | 28° /11° | 10.8 mm | 7 | |
| Sept. 4 |  Cloudy | 27° /12° | 0 mm | 6 | |
| Sept. 5 |  Overcast | 28° /15° | 1 mm | 6 | |
| Sept. 6 |  Patchy rain possible | 23° /9° | 1.3 mm | 5 | |
| Sept. 7 | Patchy rain possible | 21° /6° | 0.2 mm | 5 | |
| Sept. 8 | Mist | 23° /6° | 0 mm | 6 | |
| Sept. 9 | Mist | 27° /8° | 0 mm | 6 | |
| Sept. 10 | Fog | 28° /11° | 0 mm | 6 | |
| Sept. 11 | Light rain shower | 25° /13° | 4.6 mm | 6 | |
| Sept. 12 | Fog | 26° /12° | 0 mm | 6 | |
| Sept. 13 | Mist | 27° /14° | 0 mm | 6 | |
| Sept. 14 | Mist | 29° /12° | 0 mm | 6 | |
| Sept. 15 | Mist | 30° /14° | 0 mm | 7 | |
| Sept. 16 | Light rain shower | 30° /14° | 0.5 mm | 7 | |
| Sept. 17 | Sunny | 27° /11° | 0.6 mm | 6 | |
| Sept. 18 | Mist | 28° /10° | 0 mm | 6 | |
| Sept. 19 |  Moderate or heavy rain with thunder | 27° /12° | 16.6 mm | 6 | |
| Sept. 20 | Light rain shower | 26° /16° | 10.4 mm | 6 | |
| Sept. 21 | Fog | 26° /15° | 1.2 mm | 6 | |
| Sept. 22 | Cloudy | 25° /14° | 11.2 mm | 6 | |
| Sept. 23 | Mist | 25° /11° | 0 mm | 5 | |
| Sept. 24 |  Patchy light drizzle | 22° /12° | 0.2 mm | 5 | |
| Sept. 25 | Fog | 23° /12° | 1.7 mm | 5 | |
| Sept. 26 | Fog | 26° /10° | 10.3 mm | 6 | |
| Sept. 27 | Light rain shower | 25° /11° | 1.5 mm | 6 | |
| Sept. 28 | Cloudy | 24° /14° | 0 mm | 5 | |
| Sept. 29 | Mist | 25° /11° | 0 mm | 6 | |
| Sept. 30 | Fog | 28° /14° | 0 mm | 6 | |
| Next | |||||
Important Notice
Our weather forecast for Winnebago County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Winnebago County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Winnebago County in September - FAQ
What are the expected maximum and minimum temperatures in Winnebago County during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Winnebago County during September?
Moderate rainfall is anticipated in Winnebago County during September, with a total of 62.6 mm spread over approximately 11 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Winnebago County during September?
The average wind speed in Winnebago County during September is 18 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Winnebago County
Explore the daily rainfall trends and prepare for Winnebago Countys September weather 💧
UV exposure in Winnebago County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Top locations in Winnebago County
Select a location for an accurate weather forecast
More Locations Quick links
More Winnebago County weather pages
You are here
Where is Winnebago County?Get accurate weather forecasts for Winnebago County, located at latitude 42.271 and longitude -89.094. Stay updated with localized weather information tailored for Winnebago County.
Found a mistake?
We appreciate your attention to details. Tell us here.