Click on a day for an hourly weather forecast
The temperatures in Porsgrunn in September are usually low and can range between 11°C and 16°C.
You can expect about 3 to 8 days of rain in Porsgrunn 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 Porsgrunn in September 2026.
If you’re planning to visit Porsgrunn in the near future, we highly recommend that you review the 14 day weather forecast for Porsgrunn before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 1° / -2° | 5 | 15 | 11 | 125 mm | Awful | Porsgrunn in January |
| February | 1° / -2° | 6 | 11 | 12 | 104 mm | Awful | Porsgrunn in February |
| March | 4° / 1° | 5 | 19 | 6 | 81 mm | Awful | Porsgrunn in March |
| April | 9° / 4° | 4 | 24 | 2 | 50 mm | Bad | Porsgrunn in April |
| May | 13° / 8° | 6 | 25 | 0 | 103 mm | Ok | Porsgrunn in May |
| June | 17° / 12° | 5 | 25 | 0 | 97 mm | Good | Porsgrunn in June |
| July | 19° / 14° | 7 | 24 | 0 | 123 mm | Ok | Porsgrunn in July |
| August | 19° / 14° | 7 | 24 | 0 | 152 mm | Ok | Porsgrunn in August |
| September | 16° / 11° | 6 | 24 | 0 | 136 mm | Good | Porsgrunn in September |
| October | 11° / 7° | 10 | 21 | 0 | 167 mm | Bad | Porsgrunn in October |
| November | 6° / 4° | 9 | 17 | 4 | 158 mm | Awful | Porsgrunn in November |
| December | 3° / 0° | 9 | 14 | 8 | 134 mm | Awful | Porsgrunn in December |