Hillsborough Weather in September

The climate in Hillsborough during September can be summarized as warm, humid and a little damp.

September is in the fall / autumn in Hillsborough and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 27°C (81°F), whilst at night 14°C (58°F) is normal.

On average September is the 2nd driest month of the year in Hillsborough with around 82mm 3.2 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 7.9 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 Hillsborough in September 2025.