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The temperatures in Northern Ireland in September are usually low and can range between 10°C and 16°C.
You can expect about 3 to 8 days of rain in Northern Ireland 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 Northern Ireland in September 2025.
If you’re planning to visit Northern Ireland in the near future, we highly recommend that you review the 14 day weather forecast for Northern Ireland before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 7° / 3° | 11 | 17 | 4 | 105 mm | Awful | Northern Ireland in January |
| February | 7° / 3° | 11 | 13 | 5 | 113 mm | Awful | Northern Ireland in February |
| March | 9° / 3° | 10 | 19 | 2 | 99 mm | Awful | Northern Ireland in March |
| April | 11° / 5° | 7 | 22 | 1 | 82 mm | Bad | Northern Ireland in April |
| May | 14° / 7° | 8 | 23 | 0 | 97 mm | Ok | Northern Ireland in May |
| June | 16° / 10° | 8 | 22 | 0 | 121 mm | Ok | Northern Ireland in June |
| July | 17° / 11° | 9 | 22 | 0 | 130 mm | Ok | Northern Ireland in July |
| August | 17° / 11° | 10 | 21 | 0 | 149 mm | Ok | Northern Ireland in August |
| September | 16° / 10° | 7 | 23 | 0 | 99 mm | Ok | Northern Ireland in September |
| October | 13° / 8° | 10 | 21 | 0 | 132 mm | Bad | Northern Ireland in October |
| November | 9° / 6° | 9 | 20 | 1 | 123 mm | Bad | Northern Ireland in November |
| December | 7° / 4° | 9 | 20 | 2 | 110 mm | Awful | Northern Ireland in December |
For a more accurate weather forecast please select a city