Click on a day for an hourly weather forecast
The temperatures in Duluth in September are quite cold with temperatures between 9°C and 20°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Duluth 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 Duluth in September 2025.
If you’re planning to visit Duluth in the near future, we highly recommend that you review the 14 day weather forecast for Duluth before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -8° / -16° | 2 | 8 | 21 | 16 mm | Awful | Duluth in January |
| February | -6° / -15° | 2 | 8 | 19 | 21 mm | Awful | Duluth in February |
| March | 2° / -6° | 5 | 12 | 13 | 32 mm | Awful | Duluth in March |
| April | 8° / -1° | 5 | 18 | 7 | 50 mm | Bad | Duluth in April |
| May | 17° / 5° | 6 | 25 | 1 | 58 mm | Good | Duluth in May |
| June | 22° / 10° | 5 | 25 | 0 | 63 mm | Good | Duluth in June |
| July | 26° / 14° | 4 | 27 | 0 | 56 mm | Perfect | Duluth in July |
| August | 25° / 13° | 3 | 28 | 0 | 51 mm | Perfect | Duluth in August |
| September | 20° / 9° | 3 | 27 | 0 | 37 mm | Good | Duluth in September |
| October | 11° / 3° | 4 | 24 | 3 | 42 mm | Bad | Duluth in October |
| November | 3° / -3° | 4 | 16 | 10 | 26 mm | Awful | Duluth in November |
| December | -5° / -11° | 4 | 11 | 17 | 26 mm | Awful | Duluth in December |