May 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 May

May, the last month of the spring, in San Juan, is another warm month, with average temperature fluctuating between 82.4°F (28°C) and 76.6°F (24.8°C).

Temperature

In San Juan, Puerto Rico, the average high-temperature is practically the same as in April - a still warm 82.4°F (28°C). The average low-temperature, in San Juan, is 76.6°F (24.8°C).

Heat index

In May, the average heat index is evaluated at a tropical 89.4°F (31.9°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. 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 'felt air temperature', 'apparent temperature', 'real feel', or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (clothing, wind, metabolic differences). 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. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

May through July, with an average relative humidity of 79%, are most humid months in San Juan.

Rainfall

In San Juan, during 14.8 rainfall days, 1.06" (27mm) of precipitation is typically accumulated. In San Juan, Puerto Rico, during the entire year, the rain falls for 159.9 days and collects up to 12.01" (305mm) of precipitation.

Ocean temperature

In San Juan, the average water temperature is 81.5°F (27.5°C).
Note: Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

In May, the average length of the day is 13h.

Sunshine

In May, the average sunshine in San Juan is 10.7h.

UV index

Months with the highest UV index are April through November, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high threat to health from unsafe exposure to the UV radiation for average individuals.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. 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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in May in San Juan?

In May, in San Juan, the average high-temperature is 82.4°F (28°C), and the average low-temperature is 76.6°F (24.8°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), that combines relative humidity and air temperature, in May is appraised at 89.4°F (31.9°C).

What is the most humid month in San Juan?

May through July, with an average relative humidity of 79%, are most humid months.

What is the average humidity in May in San Juan?

The average relative humidity in May in San Juan, Puerto Rico, is 79%.

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

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

What is the ocean temperature in May in San Juan?

In May, the average ocean temperature in San Juan is 81.5°F (27.5°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.

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

In May, the average length of the day in San Juan is 13h.

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

The average sunshine in May in San Juan is 10.7h.

When is 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.

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

In May, the average daily maximum UV index in San Juan, Puerto Rico, is 7. A UV Index reading of 6 to 7 represents a high health threat from the exposure to the Sun's UV rays.

Average temperature in May
San Juan, PR

Average temperature in May - San Juan, PR
  • Average high temperature in May: 82.4°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 May: 76.6°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 May
San Juan, PR

Average pressure in May - San Juan, PR
  • Average pressure in May: 29.98"

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 May
San Juan, PR

Average wind speed in May - San Juan, PR
  • Average wind speed in May: 9.1mph

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 May
San Juan, PR

Average humidity in May - San Juan, PR
  • Average humidity in May: 79%

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 May
San Juan, PR

Average rainfall in May - San Juan, PR
  • Average rainfall in May: 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 May
San Juan, PR

Average rainfall days in May - San Juan, PR
  • Average rainfall days in May: 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 May
San Juan, PR

Average sea temperature in May - San Juan, PR
  • Average sea temperature in May: 81.5°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 May /
Average sunshine in May
San Juan, PR

Average daylight in May / Average sunshine in May - San Juan, PR
  • Average daylight in May: 13h

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 May: 10.7h

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 May
San Juan, PR

Average sunshine days in May - San Juan, PR
  • Average sunshine days in May: 10.9 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 May
San Juan, PR

Average UV index in May - San Juan, PR
  • Average UV index in May: 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 May
San Juan, PR

Average cloud cover in May - San Juan, PR
  • Average cloud cover in May: 34

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 May
San Juan, PR

Average visibility in May - San Juan, PR
  • Average visibility in May: 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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