The temperatures in Shannon in September are usually low and can range between 10°C and 17°C.
You can expect about 3 to 8 days of rain in Shannon 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 Shannon in September 2025.
If you’re planning to visit Shannon in the near future, we highly recommend that you review the 14 day weather forecast for Shannon before you arrive.
Temperatures
17° / 10°
Rainy Days
6
Snowy Days
0
Dry Days
24
Rainfall
88
mm
Sun Hours
2.7
Hrs
