San Juan Weather in August

The climate in San Juan during August can be summarized as very hot, humid and reasonably dry.

August is in the summer in San Juan and is typically the warmest month of the year. Daytime maximum temperatures average around a steamy 36°C (96°F), whilst at night 24°C (76°F) is normal.

On average August is the 5th wettest month of the year in San Juan with around 57mm 2.2 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 9.5 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 San Juan in August 2025.