Click on a day for an hourly weather forecast
The temperatures in Oshkosh in September are comfortable with low of 13°C and and high up to 21°C.
You can expect about 3 to 8 days of rain in Oshkosh 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 Oshkosh in September 2025.
If you’re planning to visit Oshkosh in the near future, we highly recommend that you review the 14 day weather forecast for Oshkosh before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -5° / -12° | 8 | 19 | 4 | 35 mm | Awful | Oshkosh in January |
| February | -4° / -11° | 7 | 16 | 4 | 38 mm | Awful | Oshkosh in February |
| March | 4° / -4° | 6 | 20 | 4 | 73 mm | Awful | Oshkosh in March |
| April | 10° / 2° | 8 | 19 | 3 | 113 mm | Awful | Oshkosh in April |
| May | 18° / 9° | 8 | 23 | 0 | 122 mm | Ok | Oshkosh in May |
| June | 23° / 15° | 9 | 21 | 0 | 122 mm | Good | Oshkosh in June |
| July | 26° / 17° | 8 | 23 | 0 | 102 mm | Good | Oshkosh in July |
| August | 25° / 17° | 8 | 23 | 0 | 104 mm | Good | Oshkosh in August |
| September | 21° / 13° | 7 | 23 | 0 | 90 mm | Ok | Oshkosh in September |
| October | 14° / 6° | 7 | 23 | 0 | 98 mm | Ok | Oshkosh in October |
| November | 6° / 0° | 6 | 23 | 1 | 59 mm | Bad | Oshkosh in November |
| December | -1° / -7° | 8 | 19 | 4 | 54 mm | Awful | Oshkosh in December |