Thompson Falls Weather in September

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

September is in the fall / autumn in Thompson Falls and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 21°C (71°F), whilst at night 2°C (35°F) is normal.

On average September is the 3rd driest month of the year in Thompson Falls with around 41mm 1.6 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 8.9 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 Thompson Falls in September 2025.