Click on a day for an hourly weather forecast
The temperatures in Bar Harbor 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 Bar Harbor 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 Bar Harbor in September 2025.
If you’re planning to visit Bar Harbor in the near future, we highly recommend that you review the 14 day weather forecast for Bar Harbor before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -8° | 6 | 10 | 15 | 147 mm | Awful | Bar Harbor in January |
| February | -1° / -7° | 6 | 8 | 14 | 137 mm | Awful | Bar Harbor in February |
| March | 3° / -4° | 8 | 11 | 12 | 131 mm | Awful | Bar Harbor in March |
| April | 9° / 2° | 9 | 18 | 3 | 151 mm | Awful | Bar Harbor in April |
| May | 15° / 7° | 9 | 22 | 0 | 125 mm | Ok | Bar Harbor in May |
| June | 20° / 11° | 7 | 23 | 0 | 134 mm | Ok | Bar Harbor in June |
| July | 23° / 15° | 5 | 27 | 0 | 97 mm | Perfect | Bar Harbor in July |
| August | 24° / 15° | 4 | 27 | 0 | 93 mm | Perfect | Bar Harbor in August |
| September | 20° / 12° | 5 | 25 | 0 | 97 mm | Good | Bar Harbor in September |
| October | 14° / 7° | 7 | 23 | 1 | 161 mm | Ok | Bar Harbor in October |
| November | 7° / 1° | 7 | 18 | 5 | 147 mm | Awful | Bar Harbor in November |
| December | 2° / -3° | 8 | 12 | 11 | 191 mm | Awful | Bar Harbor in December |