August weather forecast and climate
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

The last month of the summer, August, is also a moderately hot month in San Juan, Puerto Rico, with average temperature varying between 85.1°F (29.5°C) and 79.2°F (26.2°C).

Temperature

The warmest month 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).

Heat index

The average heat index is calculated to a very hot 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. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'feels like', 'apparent temperature', or 'felt air temperature', is a measure that combines both air temperature and relative humidity into a single value that indicates how hot the weather feels. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (metabolic differences, differences in body mass, height, and shape, wind). 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 cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. 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

The average relative humidity in San Juan is 78%.

Rainfall

In San Juan, during August, the rain falls for 14.8 days and regularly aggregates up to 1.06" (27mm) of precipitation. Throughout the year, in San Juan, there are 159.9 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Ocean temperature

In San Juan, in August, 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

The average length of the day in August is 12.7h.

Sunshine

The average sunshine in San Juan, Puerto Rico, is 9.1h.

UV index

Months with the highest UV index are April through November, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from the exposure to the Sun's UV radiation for average individuals.
Note: The daily maximum UV index of 7 interpret into the following advice:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. 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. 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.
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FAQ

What 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), August is the warmest month.

What is the temperature in August in San Juan?

In August, in San Juan, 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 represents influence of the relative humidity to air temperaure, in August is evaluated 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 much does it rain in San Juan in August?

In August, in San Juan, Puerto Rico, 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 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.

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

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

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

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

What is the month with the highest UV index in San Juan?

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

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

The average daily maximum UV index in August in San Juan, Puerto Rico, is 7. A UV Index 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 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).
Months with the lowest average high temperature are January and March (79.9°F).

  • Average low temperature in August: 79.2°F

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"

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

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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%

Months with the highest relative humidity are May, June and July (79%).
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: 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).

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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

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).

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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

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

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