Wailuku Weather in September

The climate in Wailuku during September can be summarized as hot, humid and reasonably dry.

September is in the fall / autumn in Wailuku and is typically the 2nd warmest month of the year. Daytime maximum temperatures average around a muggy 28°C (82°F), whilst at night 18°C (65°F) is normal.

On average September is the 3rd driest month of the year in Wailuku with around 56mm 2.2 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 9.1 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 Wailuku in September 2025.