Click on a day for an hourly weather forecast
The temperatures in Chelmsford in September are usually low and can range between 12°C and 20°C.
You can expect about 3 to 8 days of rain in Chelmsford 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 Chelmsford in September 2025.
If you’re planning to visit Chelmsford in the near future, we highly recommend that you review the 14 day weather forecast for Chelmsford before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 7° / 2° | 8 | 19 | 4 | 75 mm | Awful | Chelmsford in January |
| February | 8° / 3° | 8 | 16 | 4 | 70 mm | Awful | Chelmsford in February |
| March | 11° / 4° | 6 | 24 | 1 | 58 mm | Ok | Chelmsford in March |
| April | 14° / 6° | 4 | 25 | 1 | 45 mm | Good | Chelmsford in April |
| May | 17° / 8° | 5 | 26 | 0 | 60 mm | Good | Chelmsford in May |
| June | 20° / 11° | 5 | 25 | 0 | 80 mm | Good | Chelmsford in June |
| July | 22° / 14° | 5 | 26 | 0 | 68 mm | Good | Chelmsford in July |
| August | 22° / 14° | 5 | 26 | 0 | 70 mm | Good | Chelmsford in August |
| September | 20° / 12° | 3 | 27 | 0 | 46 mm | Good | Chelmsford in September |
| October | 15° / 10° | 7 | 24 | 0 | 80 mm | Ok | Chelmsford in October |
| November | 11° / 6° | 6 | 23 | 0 | 68 mm | Ok | Chelmsford in November |
| December | 8° / 4° | 7 | 21 | 2 | 88 mm | Awful | Chelmsford in December |