Click on a day for an hourly weather forecast
The temperatures in West Sussex in September are usually low and can range between 12°C and 19°C.
You can expect about 3 to 8 days of rain in West 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 West Sussex in September 2025.
If you’re planning to visit West Sussex in the near future, we highly recommend that you review the 14 day weather forecast for West Sussex before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 6° / 2° | 7 | 20 | 4 | 47 mm | Awful | West Sussex in January |
| February | 7° / 2° | 8 | 15 | 5 | 49 mm | Bad | West Sussex in February |
| March | 10° / 4° | 5 | 24 | 2 | 51 mm | Bad | West Sussex in March |
| April | 13° / 5° | 4 | 26 | 0 | 40 mm | Ok | West Sussex in April |
| May | 16° / 8° | 5 | 26 | 0 | 63 mm | Good | West Sussex in May |
| June | 18° / 11° | 6 | 24 | 0 | 89 mm | Good | West Sussex in June |
| July | 21° / 13° | 6 | 25 | 0 | 89 mm | Good | West Sussex in July |
| August | 21° / 14° | 5 | 26 | 0 | 68 mm | Good | West Sussex in August |
| September | 19° / 12° | 4 | 26 | 0 | 44 mm | Good | West Sussex in September |
| October | 14° / 9° | 5 | 26 | 0 | 58 mm | Good | West Sussex in October |
| November | 10° / 6° | 6 | 23 | 1 | 45 mm | Ok | West Sussex in November |
| December | 7° / 3° | 6 | 22 | 2 | 62 mm | Bad | West Sussex in December |