Click on a day for an hourly weather forecast
The temperatures in Ulster in September are quite cold with temperatures between 9°C and 15°C, warm clothes are a must.
You can expect rain for roughly half of the month of September in Ulster. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Ulster in September 2025.
If you’re planning to visit Ulster in the near future, we highly recommend that you review the 14 day weather forecast for Ulster before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 6° / 2° | 13 | 13 | 5 | 173 mm | Awful | Ulster in January |
| February | 7° / 2° | 12 | 10 | 7 | 169 mm | Awful | Ulster in February |
| March | 9° / 3° | 12 | 15 | 4 | 129 mm | Awful | Ulster in March |
| April | 11° / 4° | 7 | 21 | 2 | 94 mm | Awful | Ulster in April |
| May | 13° / 6° | 9 | 22 | 0 | 130 mm | Bad | Ulster in May |
| June | 16° / 9° | 10 | 20 | 0 | 146 mm | Ok | Ulster in June |
| July | 17° / 11° | 11 | 20 | 0 | 164 mm | Ok | Ulster in July |
| August | 16° / 10° | 11 | 20 | 0 | 166 mm | Ok | Ulster in August |
| September | 15° / 9° | 10 | 20 | 0 | 136 mm | Ok | Ulster in September |
| October | 12° / 7° | 11 | 20 | 0 | 158 mm | Bad | Ulster in October |
| November | 8° / 4° | 12 | 17 | 1 | 181 mm | Bad | Ulster in November |
| December | 6° / 3° | 14 | 13 | 3 | 178 mm | Awful | Ulster in December |