Butte Weather in September

The climate in Butte during September can be summarized as mild and reasonably dry.

September is in the fall / autumn in Butte and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a comfortable 25°C (77°F), whilst at night 9°C (48°F) is normal.

On average September is the 5th wettest month of the year in Butte with around 59mm 2.3 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 7 days, although this may vary considerably.

On the flip side this corresponds to an average of 9.4 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 Butte in September 2025.