The temperatures in Oswego 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 Oswego 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 Oswego in September 2025.
If you’re planning to visit Oswego in the near future, we highly recommend that you review the 14 day weather forecast for Oswego before you arrive.
Temperatures
24° / 14°
Rainy Days
5
Snowy Days
0
Dry Days
25
Rainfall
113
mm
Sun Hours
10.3
Hrs