Hillsboro Weather in September

The climate in Hillsboro during September can be summarized as hot and a little damp.

September is in the fall / autumn in Hillsboro and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a warm 31°C (89°F), whilst at night 19°C (67°F) is normal.

On average September is the 3rd wettest month of the year in Hillsboro with around 84mm 3.3 inches of rain making it a a little damp 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 8.7 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 Hillsboro in September 2025.