The climate in Grand Forks during September can be summarized as mild and reasonably dry.
September is in the fall / autumn in Grand Forks and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 20°C (68°F), whilst at night 4°C (39°F) is normal.
| Daytime temperature | 19.9°C 67.8°F |
|---|---|
| Nightly temperature | 4.1°C 39.4°F |
| Average temperature | 12°C 53.6°F |
| Daily sunshine | 7 hrs |
| Avg rainfall | 33 mm 1.3 ins |
| Rainy days | 8 days |
| Sea temperature | 12°C 53.5°F |
| Humidity | 64% |
| Windspeed | 9kph 6 mph |
On average September is the driest month of the year in Grand Forks with around 33mm 1.3 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.
On the flip side this corresponds to an average of 7 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Grand Forks in September 2025.
Best places to visit in September
| Hottest month: | July | 25.3°C 77.5°F |
|---|---|---|
| Driest month: | September | 33mm 1.3ins |
| Sunniest month: | August | 9.2hrs |
| Coldest month: | January | -2.9°C 26.8°F |
| Wettest month: | December | 87mm 3.4ins |