The climate of Puerto Rico is tropical, hot all year round, with a hotter and muggy season from May to October, and a relatively cool season from December to March, with November and April as intermediate months.
As regards the rains, the hot and muggy period from May to October tends to be rainy everywhere, while in the first months in which the north-east trade winds blow (November and December, and partly January), the rains are still abundant on the slopes facing north and east.
Instead, in the southern coast there's a relative decrease in rainfall in June and July.
The north-east trade winds, which blow all year round, but especially in the cool season, starting from November, discharge moisture, which has been picked up in the sea, in the form of rain, especially on the northern side, which therefore is rainier than the southern side.
Every now and then, from December to March, the archipelago can be affected by the passage of some frontal systems from the United States, which can bring some clouds and rains, and also a cool wind, which can lower the temperature by a few degrees, although in a less noticeable way than in Cuba and Yucatan (Mexico), which are closer to the American continent; however, in these cases the temperature can drop below 10 °C (50 °F) in inland hilly areas, and around freezing in mountainous areas.

North coast

San Juan

Here are the average temperatures of the capital San Juan, located on the north coast.
San Juan - Average temperatures
Min (°C)222223242525262625252423
Max (°C)282929303132323232313029
Min (°F)727273757777797977777573
Max (°F)828484868890909090888684

In San Juan, 1,400 millimetres (55 inches) of rain per year fall, including more than 100 mm (4 in) per month between May and December, while the driest months, with about 55 mm (2.2 in) of rain per month, are February and March, that is, at the end of the period of the trade winds, when they become weaker. Here is the average precipitation.
San Juan - Average precipitation

Anyway, the rains in Puerto Rico occur mainly in the form of showers or thunderstorms, which usually do not last long, therefore the amount of sunshine is always good, as can be seen in the following table.
San Juan - Sunshine

South coast

On the south coast, in winter the temperature is slightly higher, because the prevailing winds, the northeast trade winds, come from the interior; for example, in Ponce the maximum temperature in January and February is 30 °C (86 °F).


Here are the average temperatures in Ponce.
Ponce - Average temperatures
Min (°C)191919212223232323222120
Max (°C)303030313132333332323131
Min (°F)666666707273737373727068
Max (°F)868686888890919190908888

By contrast, along the southern coast, which is sheltered from the trade winds, rainfall often drops below 1,000 mm (40 in) per year, and winter is particularly dry, as happens in La Parguera and Ponce, but also June and July are not very rainy.
Here is the average precipitation in Ponce.
Ponce - Average precipitation

The small island called Isla Mona, to the west, is almost arid, while Vieques, to the east, is a bit rainier, since it receives 1,070 mm (42 in) of rain per year.

Puerto Rico

Sea temperature

The sea in Puerto Rico is warm enough for swimming all year round: the water temperature ranges from 26 °C (79 °F) from January to March, to 29 °C (84 °F) from August to October, as can be seen from the sea temperature at San Juan.
San Juan - Sea temperature
Temp (°C)262626272728282929292827
Temp (°F)797979818182828484848281

Hills and mountains

The interior of Puerto Rico is crossed by a mountain range called Cordillera Central.
At hill or mountain altitudes, the temperature is lower: for example, in Adjuntas, at 500 metres (1,600 feet) above sea level, highs range from 25 °C (77 °F) in winter, to 29 °C (77 to 84 °F) in summer, while on Cerro Maravilla, the fourth highest peak on the island, at 1,200 metres (3,900 feet), highs range from 20 °C (68 °F) in winter, to 23 °C (73 °F) in summer.
Here are the average temperatures of Cerro Maravilla.
Cerro Maravilla - Average temperatures
Min (°C)141313141516171716161514
Max (°C)202021212123232323232221
Min (°F)575555575961636361615957
Max (°F)686870707073737373737270

The rainiest areas are the north slopes of the Cordillera Central, where there is no real dry season, and in particular those of the Caribbean National Forest (or El Yunque): on Pico del Este, about 1,000 metres (3,300 feet) above sea level, 4,300 mm (170 in) of rain per year fall.


From June to November the archipelago can be hit by tropical storms and hurricanes, with a higher probability between August and October. The archipelago was hit hard by Hurricane Georges in September 1998, and by Hurricane Maria in September 2017.
However, even not very intense tropical storms can produce heavy rains in the inland mountain areas, which can cause landslides and floods.

When to go

In general, the coolest and least rainy period in Puerto Rico runs from December to March, which is also outside of the hurricane season; more in particular, the best time is February-March along the north and east coasts, and from December to March along the south and west coast, because they are generally the least rainy periods. In April there is a certain increase in rainfall, especially in inland areas, while the rains on the southern coast are still quite rare.
In summer, the heat is sweltering and showers are frequent, although they generally occur in the form of downpours and thunderstorms, which soon make room for the sun. However, there is a certain risk of tropical storms and hurricanes. If you want to visit Puerto Rico in summer, you may prefer the south coast, which is less rainy, especially in June and July, when there is a certain decrease in precipitation, in addition, the risk of hurricanes is lower than in August.
The Americans have introduced the habit of using air conditioning, so inside buildings the temperature is often much lower than outdoors, so it can be useful to bring some warmer articles of clothing, at least for those who are sensitive to cold.

What to pack

From December to April: light clothes, a sweatshirt for the evening.
From May to November: tropics-friendly, lightweight clothing, possibly a light sweatshirt and a light raincoat for thunderstorms; a light sweatshirt and pashmina for airconditioned places.