August weather forecast
San Juan, PR

August transitions San Juan into a slightly cooler month while still maintaining notable summer characteristics. The month records the highest sea temperature of the year at 29.1°C (84.4°F), inviting an array of beach activities. Rainfall measures at 27mm (1.06"), providing intermittent respite from the sun-bathed cityscape. The wind speed slightly reduces, and so do the sunlight hours. Together, these conditions constitute a subtly tempered yet still radiant summer month.

Temperature

August stands out as San Juan's warmest month, with temperatures ranging between an average high of 29.5°C (85.1°F) and a low of 26.2°C (79.2°F).

Heat index

The heat index value for August is estimated at a fiery hot 36°C (96.8°F). Preventive measures are required to mitigate the risk of heat cramps and heat exhaustion. Continuous activity may precipitate heatstroke.
Remember that heat index calculations are made for conditions in the shade with light wind. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', joins air temperature with relative humidity to produce a temperature perception for humans. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are largely significant for babies and toddlers. Children frequently do not comprehend the need for rest and hydration. Thirst is an advanced stage of dehydration - staying hydrated, especially during extended physical exercises, is essential.
The evaporation of sweat is a natural cooling mechanism of the human body, facilitated by perspiration. With an abundance of moisture present in the air, the process of evaporation becomes less effective, and the body fails to cool down as it should, leading to the sensation of overheating. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

In August, the average relative humidity is 78%.

Rainfall

In San Juan, during August, the rain falls for 14.8 days and regularly aggregates up to 27mm (1.06") of precipitation. In San Juan, during the entire year, the rain falls for 159.9 days and collects up to 305mm (12.01") of precipitation.

Ocean temperature

In San Juan, the average seawater temperature in August is 29.2°C (84.6°F).
Note: Temperatures between 25°C (77°F) and 29°C (84.2°F) in water are ideal for swimming, diving, and other activities, providing enjoyment and comfort for extended durations.

Daylight

In San Juan, Puerto Rico, the average length of the day in August is 12h and 44min.
On the first day of August, sunrise is at 6:02 am and sunset at 6:59 pm. On the last day of the month, sunrise is at 6:09 am and sunset at 6:39 pm AST.

Sunshine

In August, the average sunshine is 9.1h.

UV index

The months with the highest UV index are April through November, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum daily UV index of 7 in August interprets into the following recommendations:
Elude overexposure. Fair-skinned people could get burnt in less than 20 minutes. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.