La Unión Weather in September

The climate in La Unión during September can be summarized as very hot and reasonably dry.

September is in the fall / autumn in La Unión and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a warm 36°C (97°F), whilst at night 23°C (74°F) is normal.

On average September is the 3rd wettest month of the year in La Unión with around 53mm 2.1 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 4 days, although this may vary considerably.

On the flip side this corresponds to an average of 8 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 La Unión in September 2025.