The climate in Big Timber during September can be summarized as mild and reasonably dry.
September is in the fall / autumn in Big Timber and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 21°C (70°F), whilst at night 5°C (40°F) is normal.
| Daytime temperature | 21.1°C 69.9°F | 
|---|---|
| Nightly temperature | 4.6°C 40.2°F | 
| Average temperature | 12.8°C 55°F | 
| Daily sunshine | 9.4 hrs | 
| Avg rainfall | 37 mm 1.5 ins | 
| Rainy days | 8 days | 
| Sea temperature | 14.5°C 58.1°F | 
| Humidity | 52% | 
| Windspeed | 15.8kph 10 mph | 
On average September is the 4th wettest month of the year in Big Timber with around 37mm 1.5 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 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 Big Timber in September 2025.
Best places to visit in September
| Hottest month: | July | 28.6°C 83.5°F | 
|---|---|---|
| Driest month: | February | 13mm 0.5ins | 
| Sunniest month: | July | 12.6hrs | 
| Coldest month: | January | 0.4°C 32.7°F | 
| Wettest month: | May | 76mm 3ins |