August weather forecast and climate
San Juan, PR

An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
The last month of the summer, August, is also a moderately hot month in San Juan, Puerto Rico, with temperature in the range of an average low of 79.2°F (26.2°C) and an average high of 85.1°F (29.5°C).

Temperature

August is the warmest month, with an average high-temperature of 85.1°F (29.5°C) and an average low-temperature of 79.2°F (26.2°C).

Heat index

In August, the average heat index is appraised at a torrid 96.3°F (35.7°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'felt air temperature', 'feels like', or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like wind, clothing, metabolic differences, and activity influence one's weather impression. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In San Juan, the average relative humidity in August is 78%.

Rainfall

In San Juan, during 14.8 rainfall days, 1.06" (27mm) of precipitation is typically accumulated. Throughout the year, in San Juan, Puerto Rico, there are 159.9 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Ocean temperature

In San Juan, the average water temperature is 84.6°F (29.2°C).
Note: For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

In San Juan, the average length of the day in August is 12.7h.

Sunshine

In San Juan, the average sunshine is 9.1h.

UV index

Months with the highest UV index in San Juan 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 the exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.

What is the warmest month in San Juan?

August is the warmest month in San Juan, with an average high-temperature of 85.1°F (29.5°C) and an average low-temperature of 79.2°F (26.2°C).

What is the temperature in August in San Juan?

In August, the average high-temperature is 85.1°F (29.5°C), and the average low-temperature is 79.2°F (26.2°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), that factores the actual air temperature with the relative humidity, in August is calculated to 96.3°F (35.7°C).

What is the average humidity in August in San Juan?

In San Juan, Puerto Rico, the average relative humidity in August is 78%.

How many days does it rain in August in San Juan?

In August, in San Juan, the rain falls for 14.8 days. Throughout August, 1.06" (27mm) of precipitation is accumulated.

How warm is the water in August in San Juan?

In San Juan, Puerto Rico, the average seawater temperature in August is 84.6°F (29.2°C). For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

How many hours of daylight does San Juan have in August?

In August, the average length of the day in San Juan, Puerto Rico, is 12.7h.

How long on average sun shines in August in San Juan?

The average sunshine in August in San Juan is 9.1h.

What are the months with the highest UV index in San Juan?

Months with the highest UV index in San Juan are April through November, with an average maximum UV index of 7.

What is the UV index intensity in August in San Juan?

In San Juan, Puerto Rico, the average daily maximum UV index in August is 7. A UV Index value of 6 to 7 symbolizes a high health risk from the exposure to the Sun's UV radiation.
Average temperature in August - San Juan, PR
  • Average high temperature in August: 29.5°C

The warmest month (with the highest average high temperature) is August (29.5°C).
Months with the lowest average high temperature are January and March (26.6°C).

  • Average low temperature in August: 26.2°C

Months with the highest average low temperature are August, September and October (26.2°C).
The coldest month (with the lowest average low temperature) is March (23.3°C).

Average pressure in August - San Juan, PR
  • Average pressure in August: 1014.8mbar

The month with the highest atmospheric pressure is January (1016.6mbar).
The month with the lowest atmospheric pressure is October (1012.6mbar).

Average wind speed in August - San Juan, PR
  • Average wind speed in August: 16.5km/h

The windiest month (with the highest average wind speed) is July (17.2km/h).
The calmest month (with the lowest average wind speed) is October (11.9km/h).

Average humidity in August - San Juan, PR
  • Average humidity in August: 78%

Months with the highest relative humidity are May, June and July (79%).
Months with the lowest relative humidity are February and March (76%).

Average rainfall in August - San Juan, PR
  • Average rainfall in August: 27mm

The wettest month (with the highest rainfall) is November (40mm).
The driest month (with the least rainfall) is April (14mm).

Average rainfall days in August - San Juan, PR
  • Average rainfall days in August: 14.8 days

The month with the highest number of rainy days is November (16.1 days).
The month with the least rainy days is June (10.3 days).

Average sea temperature in August - San Juan, PR
  • Average sea temperature in August: 29.2°C

The best month for swimming (with the highest average sea temperature) is September (29.4°C).
The coldest months (with the lowest average sea temperature) are February and March (26.1°C).

Average daylight in August / Average sunshine in August - San Juan, PR
  • Average daylight in August: 12.7h

The month with the longest days is June (Average daylight: 13.2h).
The month with the shortest days is December (Average daylight: 11h).

  • Average sunshine in August: 9.1h

The month with the most sunshine is June (Average sunshine: 10.9h).
The month with the least sunshine is December (Average sunshine: 6.6h).

Average sunshine days in August - San Juan, PR
  • Average sunshine days in August: 10.2 days

The month with the most sunshine days is June (13.7 days).
The month with the least sunshine days is November (9.4 days).

Average UV index in August - San Juan, PR
  • Average UV index in August: 7

Months with the highest UV index are April, May, June, July, August, September, October and November (UV index 7).
Months with the lowest UV index are January, February, March and December (UV index 6).

Average cloud cover in August - San Juan, PR
  • Average cloud cover in August: 32

The month with the most cloud cover is December (Cloud cover 35).
The month with the least cloud cover is September (Cloud cover 26).

Average visibility in August - San Juan, PR
  • Average visibility in August: 10km

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).