Click on a day for an hourly weather forecast
The temperatures in Dorchester in September are usually low and can range between 11°C and 19°C.
You can expect about 3 to 8 days of rain in Dorchester 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 Dorchester in September 2025.
If you’re planning to visit Dorchester in the near future, we highly recommend that you review the 14 day weather forecast for Dorchester before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 6° / 2° | 7 | 21 | 3 | 65 mm | Awful | Dorchester in January |
| February | 7° / 2° | 8 | 16 | 4 | 66 mm | Awful | Dorchester in February |
| March | 10° / 3° | 5 | 25 | 2 | 58 mm | Bad | Dorchester in March |
| April | 13° / 4° | 6 | 24 | 0 | 58 mm | Ok | Dorchester in April |
| May | 16° / 7° | 6 | 25 | 0 | 83 mm | Good | Dorchester in May |
| June | 19° / 10° | 6 | 24 | 0 | 98 mm | Good | Dorchester in June |
| July | 22° / 13° | 6 | 25 | 0 | 86 mm | Good | Dorchester in July |
| August | 21° / 13° | 6 | 25 | 0 | 89 mm | Good | Dorchester in August |
| September | 19° / 11° | 4 | 26 | 0 | 50 mm | Good | Dorchester in September |
| October | 14° / 8° | 6 | 25 | 0 | 78 mm | Good | Dorchester in October |
| November | 10° / 5° | 7 | 23 | 0 | 78 mm | Bad | Dorchester in November |
| December | 7° / 3° | 8 | 21 | 2 | 81 mm | Awful | Dorchester in December |