The winter season is the busiest tourist time in San Juan. This is the time that the city sees its best weather and many people visit in order to escape the cold weather back home. San Juan can become very crowded in the winter and hotels raise their room rates. Occasionally, you can find a good deal on a room during the peak season. Summer is the rainy season so this is not a popular time to visit. Spring is the best time to visit - the weather is balmy between mid-April and June, the city is far less crowded, and hotel room rates are more reasonable than during the peak winter season.

January is the coolest month of the year in the tropical locale of San Juan, Puerto Rico. The average high temperature measures in at 81°F (27°C). The average low temperature is a mild 70°F (21°C).

San Juan Weather in February: The rainfall in February is 69 mm making it the driest month of the year. The average high temperature holds steady at 81°F (27°C). However, the average low temperature increases by 2 degrees to 72°F (22°C).

In March, high temperatures increase by a single degree to 82°F (28°C). On the other hand, the low temperature average remains the same at 72°F (22°C).

April’s temperatures remain at 72°F (22°C) for the average low temperature and 82°F (28°C) for the average high temperature. With the temperatures comfortably warm, April is the last month of San Juan’s peak tourist season.

San Juan Weather in May: Temperatures continue its upward trend in May with the high temperature reaching 84°F (29°C). The low temperature average climbs a single degree to 73°F (23°C).

In June, the average high temperature peaks at 84°F (29°C) while the average low temperature hits 75°F (24°C).

July sees bright and sunny days with 9 hours of sunshine per day. The long days are matched by an average high temperature of 84°F (29°C) and an average low temperature of 75°F (24°C).

San Juan Weather in August: The heat is on for August as high temperatures climb to 86°F (30°C). With the low temperature average at 75°F (24°C), August holds the record for the hottest month of the year.

In September, the precipitation levels get quite high with 139 mm of expected rainfall. The average high and average low temperatures hold steady at 86°F (30°C) and 75°F (24°C) respectively.

October retains the same temperature averages at 86°F (30°C) for the average high temperature and 75°F (24°C) for the average low temperature.

San Juan Weather in November: The rainiest month of the year for San Juan comes in November when the expected rainfall is at 157 mm. The average high temperature decreases a couple of degrees to 84°F (29°C) while the average low temperature goes down the same amount to 73°F (23°C).

In December, the average high temperature decreases ever so slightly to 82°F (28°C). The average low temperature decreases by a single degree to 72°F (22°C). The days remain quite sunny with 8 hours of daily average sunshine.

In general, the best time to visit Puerto Rico is from mid-April to June when the very busy winter season comes to an end and just before the rainy season starts. However, for travelers who wish to come when the weather is at its best, the most ideal time to visit is during the winter months of mid-December through mid-April. The most affordable time to visit Puerto Rico is between mid-April to June while July to September has the least volume of tourists.

Resources:
NOAA
AMS