Click on a day for an hourly weather forecast
The temperatures in Porvoo in September are usually low and can range between 10°C and 15°C.
You can expect about 3 to 8 days of rain in Porvoo 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 Porvoo in September 2025.
If you’re planning to visit Porvoo in the near future, we highly recommend that you review the 14 day weather forecast for Porvoo before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -3° / -6° | 5 | 6 | 21 | 51 mm | Awful | Porvoo in January |
| February | -2° / -6° | 4 | 6 | 19 | 44 mm | Awful | Porvoo in February |
| March | 1° / -4° | 6 | 8 | 18 | 47 mm | Awful | Porvoo in March |
| April | 7° / 1° | 5 | 17 | 8 | 39 mm | Bad | Porvoo in April |
| May | 14° / 7° | 4 | 26 | 1 | 39 mm | Good | Porvoo in May |
| June | 18° / 11° | 5 | 25 | 0 | 64 mm | Good | Porvoo in June |
| July | 22° / 14° | 5 | 26 | 0 | 82 mm | Good | Porvoo in July |
| August | 20° / 14° | 5 | 26 | 0 | 100 mm | Good | Porvoo in August |
| September | 15° / 10° | 6 | 24 | 0 | 86 mm | Good | Porvoo in September |
| October | 8° / 5° | 9 | 19 | 3 | 96 mm | Awful | Porvoo in October |
| November | 4° / 1° | 8 | 14 | 8 | 80 mm | Awful | Porvoo in November |
| December | 0° / -3° | 6 | 8 | 17 | 60 mm | Awful | Porvoo in December |