Click on a day for an hourly weather forecast
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.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 8° / 3° | 10 | 20 | 1 | 100 mm | Bad | Shannon in January |
| February | 9° / 3° | 9 | 17 | 2 | 94 mm | Awful | Shannon in February |
| March | 10° / 3° | 7 | 22 | 1 | 84 mm | Bad | Shannon in March |
| April | 12° / 4° | 6 | 24 | 0 | 76 mm | Ok | Shannon in April |
| May | 15° / 7° | 7 | 24 | 0 | 87 mm | Ok | Shannon in May |
| June | 17° / 9° | 6 | 24 | 0 | 99 mm | Good | Shannon in June |
| July | 19° / 11° | 7 | 24 | 0 | 97 mm | Ok | Shannon in July |
| August | 18° / 11° | 6 | 25 | 0 | 98 mm | Good | Shannon in August |
| September | 17° / 10° | 6 | 24 | 0 | 88 mm | Good | Shannon in September |
| October | 14° / 8° | 7 | 24 | 0 | 89 mm | Ok | Shannon in October |
| November | 10° / 5° | 9 | 21 | 0 | 117 mm | Bad | Shannon in November |
| December | 8° / 4° | 10 | 20 | 1 | 122 mm | Bad | Shannon in December |