Click on a day for an hourly weather forecast
The temperatures in Joliet in September are comfortable with low of 14°C and and high up to 24°C.
You can expect about 3 to 8 days of rain in Joliet during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Joliet in September 2025.
If you’re planning to visit Joliet in the near future, we highly recommend that you review the 14 day weather forecast for Joliet before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -8° | 4 | 12 | 15 | 81 mm | Awful | Joliet in January |
| February | 0° / -7° | 4 | 11 | 13 | 85 mm | Awful | Joliet in February |
| March | 8° / 1° | 8 | 17 | 7 | 111 mm | Awful | Joliet in March |
| April | 14° / 5° | 8 | 19 | 2 | 154 mm | Bad | Joliet in April |
| May | 21° / 12° | 10 | 21 | 0 | 199 mm | Ok | Joliet in May |
| June | 26° / 17° | 10 | 20 | 0 | 220 mm | Good | Joliet in June |
| July | 27° / 19° | 9 | 22 | 0 | 177 mm | Good | Joliet in July |
| August | 27° / 18° | 8 | 23 | 0 | 154 mm | Good | Joliet in August |
| September | 24° / 14° | 6 | 24 | 0 | 116 mm | Perfect | Joliet in September |
| October | 16° / 8° | 7 | 24 | 0 | 134 mm | Ok | Joliet in October |
| November | 8° / 2° | 5 | 21 | 4 | 79 mm | Bad | Joliet in November |
| December | 2° / -3° | 5 | 16 | 10 | 78 mm | Awful | Joliet in December |