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Contents
- The climate of San Juan
- The best time to visit San Juan
- The worst time to visit San Juan
- Spring weather in San Juan
- Summer weather in San Juan
- Autumn weather in San Juan
- Winter weather in San Juan
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average sea temperature
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
An old fort building and a view of the stunning San Juan city, Puerto Rico
The climate of San Juan
San Juan, Puerto Rico, residing in the northeastern Caribbean, belongs to the Köppen Am or tropical monsoon climate classification. Regarding the city's weather dynamics throughout the year, San Juan is typically characterized by high temperatures, substantial rainfall, high humidity, and generous sunlight.
A look at the monthly climate data reveals a scenario of consistently warm temperatures throughout the year in San Juan. High temperatures show a relatively small arc across the year. The absolute high is reached in August with 85.1°F (29.5°C), while the lowest high temperature is registered in January with 79.9°F (26.6°C). The lowest temperatures follow a similar trend, inching from 74.7°F (23.7°C) in January to reach a summit of 79.2°F (26.2°C) from August through October.
San Juan's climate is also distinguished by its ample humidity and rainfall. Humidity levels mildly fluctuate, lingering in the high 70s in terms of percentage year-round. Rainfall in the city shows more variance. Over the course of the year, the amount of rainfall shows an increase, starting from 0.59" (15mm) in February, peaking at 1.57" (40mm) in November, and settling back to 0.98" (25mm) in December.
Together with humidity and rainfall, San Juan enjoys plenty of sunshine. On average, the city experiences more than ten hours of daylight throughout the year. However, the actual sunshine duration varies between 6.6 hours during December and up to 10.9 hours in June.
A look at the monthly climate data reveals a scenario of consistently warm temperatures throughout the year in San Juan. High temperatures show a relatively small arc across the year. The absolute high is reached in August with 85.1°F (29.5°C), while the lowest high temperature is registered in January with 79.9°F (26.6°C). The lowest temperatures follow a similar trend, inching from 74.7°F (23.7°C) in January to reach a summit of 79.2°F (26.2°C) from August through October.
San Juan's climate is also distinguished by its ample humidity and rainfall. Humidity levels mildly fluctuate, lingering in the high 70s in terms of percentage year-round. Rainfall in the city shows more variance. Over the course of the year, the amount of rainfall shows an increase, starting from 0.59" (15mm) in February, peaking at 1.57" (40mm) in November, and settling back to 0.98" (25mm) in December.
Together with humidity and rainfall, San Juan enjoys plenty of sunshine. On average, the city experiences more than ten hours of daylight throughout the year. However, the actual sunshine duration varies between 6.6 hours during December and up to 10.9 hours in June.
The best time to visit San Juan
Outdoor enthusiasts and beachgoers may consider the dry and sunny period from March to June as the ideal time to visit San Juan. During these months, high temperatures oscillate from 81.1°F (27.3°C) in March to 84.2°F (29°C) in June, and low temperatures trend similarly from 75.2°F (24°C) to 78.3°F (25.7°C). The rainfall is lower than other months with a measure from 0.55" (14mm) in April to a maximum of 0.71" (18mm) in June. These months also boast enhanced sunshine duration and daylight hours, peaking at 13.2 hours of daylight and 10.9 hours of actual sunshine in June.
The worst time to visit San Juan
If one seeks to avoid heavy rainfall, November could be deemed as the least suitable month for a visit to San Juan. Relative to other months, November sees the highest volume of rainfall, 1.57" (40mm) and has the most number of rainfall days, 16.1 days on average. Despite high temperatures averaging from a high of 83.1°F (28.4°C) to a low of 77.9°F (25.5°C), the increased rainfall could potentially hamper outdoor activities.
Spring weather in San Juan
San Juan's spring extends from March to May and is characterized by climbing temperatures, rising from 81.1°F (27.3°C) to 82.4°F (28°C) as daytime highs, and from 75.2°F (24°C) to 76.6°F (24.8°C) as nighttime lows. Rainfall quantities also increase, advancing from 0.55" (14mm) in March to 1.06" (27mm) in May.
Summer weather in San Juan
Running from June through August, San Juan's summer carries the uppermost temperatures in the year, rising from 84.2°F (29°C) in June to the peak of 85.1°F (29.5°C) in August. Similarly, the lowest temperatures ascend from 78.3°F (25.7°C) in June to 79.2°F (26.2°C) in August. June represents the sunniest month of the year, with 10.9 hours of actual sunshine.
Autumn weather in San Juan
San Juan's autumn, from September to November, brings about a decline in temperatures, falling from a high of 84.9°F (29.4°C) in September to 83.1°F (28.4°C) in November. The lowest temperatures remain somewhat constant at 79.2°F (26.2°C) in September and October before dropping to 77.9°F (25.5°C) in November. Notably, this season also spots the peak in rainfall with November being the rainiest month, registering 1.57" (40mm).
Winter weather in San Juan
Winter temperatures in San Juan, from December to February, show a marginal descent, falling from 80.8°F (27.1°C) to 79.9°F (26.6°C) as daily highs and from 75.9°F (24.4°C) to 74.7°F (23.7°C) at night. In terms of rainfall, the winter months see a decrease, moving from 0.98" (25mm) in December to 0.59" (15mm) in February, the driest month of the year.
Weather in January
In San Juan, a tendency towards a cooler climate makes January distinctive. The average high sits slightly below the annual norm at 79.9°F (26.6°C), while the sea temperature sees a slight dip to 79.7°F (26.5°C). Despite less daylight and sunshine hours, clear skies remain prevalent with cloud cover at a minimal 32%. Weather in January »
Weather in February
San Juan experiences a continuation of mild temperatures from January into February. There is a nominal increase in both high temperatures and sea temperatures, averaging 80.1°F (26.7°C) and 78.9°F (26.1°C), respectively. The sun begins to make a more noticeable presence, yet rainfall sees a decrease to 0.59" (15mm) over approximately 12 days. Weather in February »
Weather in March
March in San Juan welcomes the onset of spring with a rise in temperatures. Noticeably, the month endures the highest amount of rainfall days at 12.8, registering a total of 0.87" (22mm) of rainfall. The sea temperature marginally rises to 79.1°F (26.2°C) in line with an increase in sunshine hours to 8.6 per day. Weather in March »
Weather in April
April invites a new chapter of weather in San Juan. The increase to 81.1°F (27.3°C) in average high temperatures accompanies a rise in sea temperatures to 80.5°F (26.9°C), signaling the onset of a warmer climate. Sunshine hours continue to increase, yet cloud cover remains relatively constant. Weather in April »
Weather in May
May in San Juan heralds the arrival of the city's warmest period. The average high temperature escalates to 82.4°F (28°C), as does the sea temperature, reaching 81.5°F (27.5°C). Notably, the month has the year's maximum rainfall of 1.06" (27mm). Weather in May »
Weather in June
June in San Juan is characterized by peak summer conditions, with average high temperatures reaching 84.2°F (29°C). The sun dominates the sky for an impressive 10.9 hours per day, yet rainfall remains moderate at 0.71" (18mm). Sea temperatures also rise to an appealing 82.8°F (28.2°C), encouraging beachside relaxation amidst the season’s swelter. Weather in June »
Weather in July
July continues the summer heat in San Juan with the year's highest average high temperature of 84.2°F (29°C). Interestingly, the month also sees the year's maximum wind speed at a moderate 10.7mph (17.2km/h). The sea temperature swings to a comfortable 83.6°F (28.7°C) fostering waterside activities. Weather in July »
Weather in August
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 84.4°F (29.1°C), inviting an array of beach activities. Weather in August »
Weather in September
September in San Juan witnesses a minor pullback from the robust heat of summer. The city enjoys the highest sea temperature of the year at 84.9°F (29.4°C), soothing the still active summer heat. A shift is evident in the wind speeds, which decrease to 8.1mph (13km/h). Weather in September »
Weather in October
October in San Juan observes a change in weather patterns as temperatures begin to cool modestly. Average high temperatures drop slightly to 84.6°F (29.2°C), well aligned with decreasing sea temperatures of 84.4°F (29.1°C). Weather in October »
Weather in November
November marks the onset of winter in San Juan with a noticeable drop in average high temperatures to 83.1°F (28.4°C). The sea temperature falls to 83.5°F (28.6°C), foreshadowing the end of the beach season. Sunshine hours dwindle to 6.7 per day, the fewest in the year. Weather in November »
Weather in December
December closes the year in San Juan with clear winter signals. Average high temperatures fall to a low of 80.8°F (27.1°C), constituting the perfect recipe for a comfortable holiday season. The sea temperature dips to 81.8°F (27.7°C), and the daylight hours decrease to 11 per day. Weather in December »
[Resources]Frequently asked questions
What are the coldest months in San Juan?
In San Juan, Puerto Rico, the coldest months are January and March, registering an average high-temperature of 79.9°F (26.6°C).
How many days does it rain in San Juan?
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.
What are the months with the lowest UV index in San Juan?
January through March and December, with an average maximum UV index of 6, are months with the lowest UV index.
What are the least humid months in San Juan?
The months with the lowest humidity are February and March, with an average relative humidity of 76%.
When is the ocean coldest in San Juan?
February and March, with an average ocean temperature of 79°F (26.1°C), are months with the coldest seawater in San Juan.
What is the driest month in San Juan?
The month with the least rainfall in San Juan, Puerto Rico, is April, when the rain falls for 12.4 days and typically collects 0.55" (14mm) of precipitation.
What are the months 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.
What is the most humid month in San Juan?
The months with the highest humidity are May through July, with an average relative humidity of 79%.
When are the longest days in San Juan?
June has the longest days of the year, with an average of 13h and 12min of daylight.
What month has the most sunshine in San Juan?
The month with the most sunshine in San Juan, Puerto Rico, is June, with an average of 10.9h of sunshine.
What is the hottest time of year in San Juan?
August is the month when San Juan, Puerto Rico, experiences its warmest temperatures, averaging a high of 85.1°F (29.5°C) and a low of 79.2°F (26.2°C).
When is the ocean warmest in San Juan?
The month with the warmest seawater is September, with an average ocean temperature of 84.9°F (29.4°C).
What is the rainiest month in San Juan?
The month with the most rainfall in San Juan, Puerto Rico, is November, when the rain falls for 16.1 days and typically aggregates up to 1.57" (40mm) of precipitation.
What is the month with the shortest days in San Juan?
The month with the shortest days in San Juan is December, with an average of 11h and 0min of daylight.
Is there Daylight Saving Time (DST) in San Juan?
San Juan, Puerto Rico, does not utilize Daylight Saving Time (DST). AST timezone is used over the entire year.
What is the month with the least sunshine in San Juan?
The month with the least sunshine in San Juan, Puerto Rico, is December, with an average of 6.6h of sunshine.
Average temperature
San Juan, PR
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).
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).
Average pressure
San Juan, PR
- Average pressure in January:
30.02"Hg - Average pressure in February:
30.02"Hg - Average pressure in March:
30.01"Hg - Average pressure in April:
29.99"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
30.01"Hg
- Average pressure in July:
30.01"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.9"Hg - Average pressure in November:
29.91"Hg - Average pressure in December:
29.98"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).
Average wind speed
San Juan, PR
- Average wind speed in January:
9.8mph - Average wind speed in February:
10.1mph - Average wind speed in March:
9.6mph - Average wind speed in April:
9.4mph - Average wind speed in May:
9.1mph - Average wind speed in June:
9.6mph
- Average wind speed in July:
10.7mph - Average wind speed in August:
10.3mph - Average wind speed in September:
8.1mph - Average wind speed in October:
7.4mph - Average wind speed in November:
7.9mph - Average wind speed in December:
9.9mph
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).
Average humidity
San Juan, PR
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%).
Average rainfall
San Juan, PR
- Average rainfall in January:
0.83" - Average rainfall in February:
0.59" - Average rainfall in March:
0.87" - Average rainfall in April:
0.55" - Average rainfall in May:
1.06" - Average rainfall in June:
0.71"
The wettest month (with the highest rainfall) is November (1.57").
The driest month (with the least rainfall) is April (0.55").
Average rainfall days
San Juan, PR
- Average rainfall days in January:
11.5 days - Average rainfall days in February:
11.9 days - Average rainfall days in March:
12.8 days - Average rainfall days in April:
12.4 days - Average rainfall days in May:
14.8 days - Average rainfall days in June:
10.3 days
- Average rainfall days in July:
13.3 days - Average rainfall days in August:
14.8 days - Average rainfall days in September:
11.7 days - Average rainfall days in October:
15.8 days - Average rainfall days in November:
16.1 days - Average rainfall days in December:
14.5 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
San Juan, PR
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).
Average daylight / Average sunshine
San Juan, PR
- Average daylight in January:
11h and 1min - Average daylight in February:
11h and 4min - Average daylight in March:
12h and 1min - Average daylight in April:
12h and 4min - Average daylight in May:
13h and 0min - Average daylight in June:
13h and 1min
- Average daylight in July:
13h and 1min - Average daylight in August:
12h and 4min - Average daylight in September:
12h and 1min - Average daylight in October:
11h and 4min - Average daylight in November:
11h and 2min - Average daylight in December:
11h and 0min
The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 0min).
- Average sunshine in January:
8h and 5min - Average sunshine in February:
8h and 5min - Average sunshine in March:
8h and 4min - Average sunshine in April:
9h and 1min - Average sunshine in May:
10h and 4min - Average sunshine in June:
10h and 5min
- Average sunshine in July:
10h and 1min - Average sunshine in August:
9h and 1min - Average sunshine in September:
9h and 2min - Average sunshine in October:
8h and 1min - Average sunshine in November:
6h and 4min - Average sunshine in December:
6h and 4min
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).
Average sunshine days
San Juan, PR
- Average sunshine days in January:
11.1 days - Average sunshine days in February:
9.8 days - Average sunshine days in March:
11.9 days - Average sunshine days in April:
11 days - Average sunshine days in May:
10.9 days - Average sunshine days in June:
13.7 days
- Average sunshine days in July:
9.8 days - Average sunshine days in August:
10.2 days - Average sunshine days in September:
12.5 days - Average sunshine days in October:
10 days - Average sunshine days in November:
9.4 days - Average sunshine days in December:
9.5 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
San Juan, PR
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).
Average cloud cover
San Juan, PR
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
San Juan, PR
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).
San Juan, Puerto Rico, USA
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