August weather forecast
San Juan, PR

An old fort building and a view of the stunning San Juan city, Puerto Rico
An old fort building and a view of the stunning San Juan city, Puerto Rico

Weather in August

August, the last month of the summer in San Juan, is another warm month, with an average temperature fluctuating between 85.1°F (29.5°C) and 79.2°F (26.2°C).

Temperature

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

Heat index

The average heat index in August is appraised at a sweltering 96.3°F (35.7°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature', 'feels like', 'apparent temperature', or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (wind, differences in body mass, height, and shape, clothing). 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 particularly important for children. 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. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 99.5°F (37.5°C) to 100.9°F (38.3°C), thermal conditions are potentially life-threatening.

Humidity

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

Rainfall

In August, in San Juan, the rain falls for 14.8 days. Throughout August, 1.06" (27mm) of precipitation is accumulated. Throughout the year, 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 any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

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

Sunshine

In San Juan, the average sunshine in August is 9.1h.

UV index

April through November, with an average maximum UV index of 7, are months with the highest UV index in San Juan. A UV Index value of 6 to 7 symbolizes a high health risk from unprotected exposure to Sun's UV rays for the average person.
Note: The daily maximum UV index of 7 in August interpret into the following advice:
Take precautions against overexposure. Protection against sun damage is needed. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.
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FAQ

What is the warmest month in San Juan?

The warmest month in San Juan is August, 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 San Juan, Puerto Rico, 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. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, in August is appraised at 96.3°F (35.7°C).

What is the average humidity in August in San Juan?

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

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

In San Juan, Puerto Rico, in August, during 14.8 rainfall days, 1.06" (27mm) of precipitation is typically accumulated.

What is the ocean temperature in August in San Juan?

In San Juan, 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.

What is the average length of the day in August in San Juan?

In San Juan, Puerto Rico, the average day length in August is 12h and 44min.

What time are sunrise and sunset in August in San Juan?

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

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

In San Juan, Puerto Rico, the average sunshine duration in August is 9.1h.

When is the highest UV index in San Juan?

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

How high is the UV index in August in San Juan?

The average daily maximum UV index in August in San Juan is 7. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.

Average temperature in August
San Juan, PR

Average temperature in August - San Juan, PR
  • Average high temperature in August: 85.1°F

The warmest month (with the highest average high temperature) is August (85.1°F).
The months with the lowest average high temperature are January and March (79.9°F).

  • Average low temperature in August: 79.2°F

The months with the highest average low temperature are August, September and October (79.2°F).
The coldest month (with the lowest average low temperature) is March (73.9°F).

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Average pressure in August
San Juan, PR

Average pressure in August - San Juan, PR
  • Average pressure in August: 29.97"Hg

The months with the highest atmospheric pressure are January and February (30.02"Hg).
The month with the lowest atmospheric pressure is October (29.9"Hg).

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Average wind speed in August
San Juan, PR

Average wind speed in August - San Juan, PR
  • Average wind speed in August: 10.3mph

The windiest month (with the highest average wind speed) is July (10.7mph).
The calmest month (with the lowest average wind speed) is October (7.4mph).

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Average humidity in August
San Juan, PR

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

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

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Average rainfall in August
San Juan, PR

Average rainfall in August - San Juan, PR
  • Average rainfall in August: 1.06"

The wettest month (with the highest rainfall) is November (1.57").
The driest month (with the least rainfall) is April (0.55").

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Average rainfall days in August
San Juan, PR

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).

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Average sea temperature in August
San Juan, PR

Average sea temperature in August - San Juan, PR
  • Average sea temperature in August: 84.4°F

The best month for swimming (with the highest average sea temperature) is September (84.9°F).
The coldest month (with the lowest average sea temperature) is February (78.9°F).

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Average daylight in August /
Average sunshine in August
San Juan, PR

Average daylight in August / Average sunshine in August - San Juan, PR
  • Average daylight in August: 12h and 44min

The month with the longest days is June (Average daylight: 13h and 13min).
The month with the shortest days is December (Average daylight: 11h and 2min).

  • Average sunshine in August: 9h and 6min

The month with the most sunshine is June (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).

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Average sunshine days in August
San Juan, PR

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).

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Average UV index in August
San Juan, PR

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

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

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Average cloud cover in August
San Juan, PR

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).

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Average visibility in August
San Juan, PR

Average visibility in August - San Juan, PR
  • Average visibility in August: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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