Click on a day for an hourly weather forecast
The temperatures in Oslo in September are quite cold with temperatures between 8°C and 16°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Oslo 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 Oslo in September 2025.
If you’re planning to visit Oslo in the near future, we highly recommend that you review the 14 day weather forecast for Oslo before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -7° | 3 | 13 | 15 | 51 mm | Awful | Oslo in January |
| February | -1° / -8° | 4 | 11 | 14 | 45 mm | Awful | Oslo in February |
| March | 3° / -5° | 6 | 16 | 10 | 46 mm | Awful | Oslo in March |
| April | 10° / 2° | 4 | 23 | 3 | 39 mm | Bad | Oslo in April |
| May | 15° / 5° | 7 | 23 | 1 | 85 mm | Ok | Oslo in May |
| June | 19° / 9° | 7 | 23 | 0 | 89 mm | Ok | Oslo in June |
| July | 21° / 11° | 7 | 24 | 0 | 99 mm | Ok | Oslo in July |
| August | 20° / 11° | 7 | 24 | 0 | 94 mm | Ok | Oslo in August |
| September | 16° / 8° | 5 | 25 | 0 | 69 mm | Good | Oslo in September |
| October | 10° / 4° | 7 | 23 | 1 | 68 mm | Bad | Oslo in October |
| November | 4° / 0° | 6 | 18 | 6 | 67 mm | Awful | Oslo in November |
| December | -1° / -5° | 6 | 14 | 11 | 58 mm | Awful | Oslo in December |