Fort Irwin Weather in September

The climate in Fort Irwin during September can be summarized as hot and very dry.

September is in the fall / autumn in Fort Irwin and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a warm 34°C (93°F), whilst at night 16°C (61°F) is normal.

On average September is the 4th driest month of the year in Fort Irwin with around 8mm 0.3 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 11.3 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 Fort Irwin in September 2025.