Click on a day for an hourly weather forecast
The temperatures in Killarney in September are quite cold with temperatures between 8°C and 16°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Killarney 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 Killarney in September 2025.
If you’re planning to visit Killarney in the near future, we highly recommend that you review the 14 day weather forecast for Killarney before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 8° / 2° | 11 | 19 | 2 | 139 mm | Awful | Killarney in January |
| February | 8° / 2° | 11 | 16 | 2 | 121 mm | Awful | Killarney in February |
| March | 10° / 2° | 7 | 22 | 2 | 82 mm | Awful | Killarney in March |
| April | 12° / 4° | 6 | 24 | 0 | 76 mm | Ok | Killarney in April |
| May | 14° / 6° | 7 | 24 | 0 | 96 mm | Ok | Killarney in May |
| June | 17° / 8° | 6 | 24 | 0 | 84 mm | Good | Killarney in June |
| July | 18° / 10° | 7 | 24 | 0 | 91 mm | Ok | Killarney in July |
| August | 17° / 10° | 7 | 24 | 0 | 92 mm | Ok | Killarney in August |
| September | 16° / 8° | 6 | 24 | 0 | 87 mm | Good | Killarney in September |
| October | 13° / 7° | 9 | 22 | 0 | 106 mm | Bad | Killarney in October |
| November | 10° / 4° | 10 | 20 | 0 | 130 mm | Bad | Killarney in November |
| December | 8° / 3° | 11 | 19 | 1 | 149 mm | Bad | Killarney in December |