Joliet (IL)
September
Weather in Joliet, Illinois for September 2026
Your guide to Joliet weather in September - trends and predictions
So far, September 2026 in Joliet shows a warmer trend than usual by 2.9 °F.
The forecast for the next days in Joliet predicts a temperature of 23.4 °F, which is cooler than the historical average.
In general, the average temperature in Joliet at the beginning of September is 28.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.7 °F by the end of September.
The climate of Joliet in September is notably wet, with an average of 12 rainy days, and a total of 86 mm of precipitation.
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Temperatures
Rain 🌧️
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18
Dry days
12
Rainy days
0
Snow days
26°/13°
Temperatures
17 km/h
Avg max wind
68 %
Avg humidity
Joliet Weather September
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Temperatures trend during September in Joliet
See the weather trend as well as the moving average line
September weather in Joliet day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /14° | 3.9 mm | 6 | |
| Sept. 2 | Sunny | 30° /15° | 0 mm | 7 | |
| Sept. 3 | Sunny | 31° /15° | 7.5 mm | 7 | |
| Sept. 4 |  Mist | 31° /15° | 0 mm | 7 | |
| Sept. 5 | Sunny | 30° /17° | 0.9 mm | 7 | |
| Sept. 6 |  Patchy rain possible | 26° /13° | 1.3 mm | 6 | |
| Sept. 7 | Sunny | 24° /10° | 0 mm | 6 | |
| Sept. 8 |  Partly cloudy | 25° /10° | 0 mm | 6 | |
| Sept. 9 | Mist | 26° /12° | 34.4 mm | 5 | |
| Sept. 10 | Partly cloudy | 28° /13° | 0.4 mm | 6 | |
| Sept. 11 | Light rain shower | 28° /15° | 8.3 mm | 7 | |
| Sept. 12 | Fog | 28° /13° | 0 mm | 7 | |
| Sept. 13 | Mist | 26° /14° | 0 mm | 6 | |
| Sept. 14 | Mist | 27° /13° | 0 mm | 7 | |
| Sept. 15 | Patchy rain possible | 29° /18° | 13.8 mm | 5.2 | |
| Sept. 16 | Patchy rain possible | 22° /19° | 5.4 mm | 2.3 | |
| Sept. 17 | Patchy rain possible | 26° /20° | 7.4 mm | 6 | |
| Sept. 18 | Patchy rain possible | 26° /19° | 4.2 mm | 6 | |
| Sept. 19 | Patchy rain possible | 24° /21° | 4.3 mm | 5 | |
| Sept. 20 | Light rain shower | 21° /17° | 7.4 mm | 5 | |
| Sept. 21 | Light rain shower | 23° /18° | 10.1 mm | 5 | |
| Sept. 22 | Sunny | 21° /14° | 0 mm | 6 | |
| Sept. 23 | Sunny | 23° /15° | 0.6 mm | 6 | |
| Sept. 24 | Sunny | 17° /10° | 0 mm | 5 | |
| Sept. 25 | Sunny | 19° /9° | 0 mm | 5 | |
| Sept. 26 | Sunny | 24° /12° | 0 mm | 6 | |
| Sept. 27 |  Overcast | 26° /15° | 0 mm | 7 | |
| Sept. 28 | Overcast | 26° /18° | 0 mm | 6 | |
| Sept. 29 | Fog | 26° /15° | 0 mm | 6 | |
| Sept. 30 | Fog | 28° /15° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Joliet 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 Joliet forecast closer to your planned date for the most up-to-date weather information.
Change Month
Joliet in September - FAQ
What are the expected maximum and minimum temperatures in Joliet during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Joliet during September?
Moderate rainfall is anticipated in Joliet during September, with a total of 86 mm spread over approximately 12 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Joliet during September?
The average wind speed in Joliet during September is 17 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Joliet
Explore the daily rainfall trends and prepare for Joliets September weather 💧
Typically, Joliet has 12 rainy days in September with a total of 86 mm of rainfall.
UV exposure in Joliet during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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