Click on a day for an hourly weather forecast
The temperatures in Sussex in September are comfortable with low of 14°C and and high up to 23°C.
You can expect about 3 to 8 days of rain in Sussex 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 Sussex in September 2025.
If you’re planning to visit Sussex in the near future, we highly recommend that you review the 14 day weather forecast for Sussex before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 0° / -6° | 6 | 15 | 11 | 113 mm | Awful | Sussex in January |
| February | 1° / -6° | 5 | 12 | 11 | 127 mm | Awful | Sussex in February |
| March | 6° / -2° | 8 | 15 | 8 | 139 mm | Awful | Sussex in March |
| April | 13° / 4° | 8 | 20 | 2 | 127 mm | Awful | Sussex in April |
| May | 20° / 10° | 7 | 24 | 0 | 102 mm | Ok | Sussex in May |
| June | 24° / 14° | 7 | 23 | 0 | 119 mm | Good | Sussex in June |
| July | 28° / 18° | 7 | 24 | 0 | 119 mm | Good | Sussex in July |
| August | 28° / 17° | 5 | 26 | 0 | 103 mm | Perfect | Sussex in August |
| September | 23° / 14° | 4 | 26 | 0 | 79 mm | Perfect | Sussex in September |
| October | 16° / 8° | 6 | 25 | 0 | 125 mm | Good | Sussex in October |
| November | 10° / 3° | 6 | 22 | 2 | 103 mm | Bad | Sussex in November |
| December | 4° / -2° | 7 | 16 | 7 | 141 mm | Awful | Sussex in December |