Puerto Rico has a tropical rainforest type of climate (Köppen climate classification Af), with a mostly hot and humid atmosphere during the year. Puerto Rico is an unincorporated territory of the United States, about 1000 miles southeast of the state of Florida. The archipelago lies in the northeastern Caribbean Sea between the US Virgin Islands and the Dominican Republic. Easterly trade winds, tropical latitudes, mountainous landscapes, and engulfment by the sea are the primary factors that influence the climate.
Puerto Rico lies 18°north of the equator and comprises of the main island of Puerto Rico and many small islands and islets. The island consists of a central mountain range and has a mountainous topography, with the highest elevation of 1340 meters at Cerro de Punta. The Cordillera Central Mountain Range blocks trade winds and causes local variations in temperatures and rainfall. Large swathes of coasts lie in the north and south, as the main island spans 110 miles from east to west but only 40 miles from north to south. Puerto Rico has more than 50 rivers and 17 lakes and is home to the tropical El Yunque National Forest.
Puerto Rico is mostly hot and humid, with two different seasons. The wet season lasts from April to November and brings more than 80% of the annual rainfall. The dry season is from December to March and sees a small drop in temperatures and humidity. The average high temperature reaches 89°F (31.7°C) at the peak of August, while the average low temperature is at its lowest of 72°F (22.2°C) in January. The northern and central regions are cooler than the south by a few degrees. The coastal lands and lower elevations are hotter than the high mountains. Sea waters are mild to warm and register in the average range of 75°F (23.9°C) to 85°F (29.4°C) over the year.
The average annual rainfall is 56" (1422.4mm), with 196 rainy days in the year. November is the wettest month of the year, and it rains at least 5" (127mm) every month during the wet season. The northern part of the archipelago is wetter than the rest. The relative humidity is mostly in the range of 70% to 80%, with an average annual number of 77%. Puerto Rico receives ample annual sunshine of 3100 hours. Tropical cyclones contribute one-fourth of the annual rainfall. Easterly winds dominate the wind pattern with average speeds of 20 to 22mph (35.4km/h).
The highest temperature on record for Puerto Rico is 103°F (39.4°C) at San Lorenzo, while the record lowest temperature is 38°F (3.3°C), set in Aibonito, in the mountains.
The best time to visit Puerto Rico
The best time to visit Puerto Rico is from January to April when the temperatures are relatively mild in the dry season. The tropical islands do not have a winter season, but the temperatures drop up to 6°F (-14.4°C) from the highs of August and September. The tourist season peaks between January to March, but people who prefer to avoid crowds like April and May. The dry season has comfortable weather and relatively lesser rainfall than the rest of the year. The windward sides of the mountains are rainier than the coast.
The worst time to visit Puerto Rico
The worst time to visit Puerto Rico is from August to October in the wet season. The conditions are hot and humid, and the heat index peaks in August. Precipitation occurs regularly in this period and contributes a significant percentage of the annual rainfall. The hurricane season is at its peak, and the probability of tropical storms is at the highest of the year. The intensity of the tropical sun is at its peak and is unbearable for people from the temperate zones of the world.
Puerto Rico is vulnerable to thunderstorms, tropical cyclones, hurricanes, typhoons, tornadoes, and high-speed winds. The islands experience the Atlantic hurricane season from June to November. The latest, category 5 Hurricane Irma in 2017, saw wind speeds up to 180mph (289.7km/h), while Hurricane Maria brought heavy rainfall of 38" (965.2mm), and large scale destruction. Hurricanes cause damages in billions of dollars and loss of human lives. Thunderstorms are frequent in the entire area, along with tropical waves and tropical cyclones. Landfalls made by storms have a severe consequence on the island's infrastructure. The islands are susceptible to seismic activity and resultant tsunamis.
Weather in January
January is usually the coldest month of the year in Puerto Rico, with the average temperatures in the warm 72°F (22.2°C) to 83°F (28.3°C) range. San Juan, the capital, is busy with tourists from all over the world, crowding the place during the New Year. Day temperatures are comfortable, while nights are pleasant, with a drop in humidity. The bright sunshine lasts for 8 hours and bearable even during peak hours. The precipitation averages up to 3.8" (96.5mm) but is generally light, and the showers are brief. Seawater temperatures of 79°F (26.1°C) are warm enough for swimming. Visibility extends for several miles on the sea as the skies remain mostly clear at the end of the hurricane season. Light sea breezes prevail on the coast during the evenings that make beach visits pleasant. Light and bright clothes are preferable, and winter wear is generally dispensable in Puerto Rico in January.
Weather in February
February sees pleasant conditions in Puerto Rico, with mostly blue skies amid little rain. The average temperatures are in the comfortable 72°F (22.2°C) to 84°F (28.9°C) range, with 8 hours of bright sunshine. Mornings begin in a cool environment, and the warm afternoon sunshine aids outdoor activities. Cruises, boats, and yachts sail in the calm waters of the San Juan Bay as well as the seawaters around the islands. The skies are mostly clear, although a light shower occasionally occurs to remind that the islands are never arid. The rainfall registers below 2.5" (63.5mm) in February, which means a rain jacket is optional during outdoor excursions. Continental cold waves rarely make as far south as Puerto Rico, and the only places where temperatures are cold are the high elevations of the mountains. Warm winter clothes are generally unnecessary in Puerto Rico in February when North America is freezing with cold.
Weather in March
March is the driest month of the year in Puerto Rico, with only 2" (50.8mm) of rain. Blue skies and calm seawaters await visitors in the warm atmosphere of the tropical islands. The average temperatures are in the 73°F (22.8°C) to 85°F (29.4°C) range, with rare extremes. The dryness brings a drop in humidity and keeps the heat index at bay. Although the afternoon sun tends to be hot, there are many who spend the entire day outdoors in the bright sunshine. Light summer clothing with sun hats is perfect for history buffs who seek to explore the old Spanish forts on the island. The clear waters and marine diversity are favorable for snorkeling and scuba diving, while the mild waters are perfect for kayaking and swimming. Light sea breezes keep the atmosphere pleasant in the evenings, as the beaches remain busy with tourists during the long daylight hours. March is a good time to visit Puerto Rico.
Weather in April
April begins the transition to the wet season in Puerto Rico with an increase in precipitation and humidity. Day temperatures average a high of 86°F (30°C), while nights are mild at 74°F (23.3°C). The skies are partly cloudy, especially at noontime, and the average precipitation is 4.7" (119.4mm) in the month. The daily sunshine lasts for 9 hours, but the humidity is bearable and keeps the heat index within acceptable limits. Air-conditioners run in many places, especially in hotels, as the tourists begin to feel the heat. The western part of the islands is best for sunbathing on the beaches and surfing on the calm waves, but it is prudent to seek shade by afternoon. The waters of the Mosquito Bay emit a blue glow by night, much to the amazement of the visitors. Expect showers in the afternoon that lower the effect of the heat in April.
Weather in May
May is the wet, hot, and humid in Puerto Rico as the rainy season takes hold in the islands. The average temperatures are in the 76°F (24.4°C) to 87°F (30.6°C) range, and the heat is oppressive. The blazing sun emits peak ultraviolet radiation at a level of 12 and makes it challenging to venture outdoors past mid-mornings. Most of the buildings, including public places and residential buildings, are white-washed to counter the blistering sunshine. The precipitation registers to the tune of 5.9" (149.9mm), with at least one wet day in two. A rain jacket is desirable, but an umbrella serves better as the heat makes it difficult to wear an extra layer of clothing. Flamenco Beach in Culebra is the most beautiful beach on the islands with white sand and many palm trees. Many budget travelers prefer May in Puerto Rico due to the slowdown of the tourist season and the resultant drop in tour prices.
Weather in June
June begins the hurricane season in Puerto Rico that brings sudden changes in the weather. Wind speeds rise dramatically, and the usually calm waters see much disturbance. Waves more than 20-feet high are common, but add thrill to surfing. The rain gauge accumulates 4.4" (111.8mm) amid a combination of sunny and cloudy days. The temperatures hover in the 78°F (25.6°C) to 88°F (31.1°C), with 9 hours of scorching sunshine every day. Tourists usually avoid the summer heat, which becomes oppressive by the second half of June. However, there are many places in the mountains, such as Cerro Maravilla, Aibonito, and Adjuntas, where the temperatures are lower by at least 6 degrees than the coast. Nights are comfortable, and San Juan sees many takers for its vibrant nightlife. Expect bright skies within minutes after heavy showers. Carry an umbrella to protect from rain and shine in June in Puerto Rico.
Weather in July
July is a hot and humid month in Puerto Rico, with an average of 280 hours of bright sunshine. The average temperatures are between 78°F (25.6°C) and 89°F (31.7°C), and the relative humidity is at 78%, the highest monthly average of the year. The skies are partly cloudy, and the 5" (127mm) of rainfall mainly occurs during thunderstorms and tropical storms. The mountains see more rain on the windward side than the low-lying lands and are generally cooler than the coast. The El Yunque rainforest is lush green, especially in the wet season, with many waterfalls in the interior. However, only adventurers explore the interior during the rainy season and that too after wearing a layer of rain protection. Expect wind speeds to be low in July, except during storms when they can be destructive. Carry an umbrella even near the coast. July is a slow season for tourism in Puerto Rico.
Weather in August
August is the hottest month of the year in Puerto Rico, with average temperatures in the 79°F (26.1°C) to 89°F (31.7°C) range. The wet month brings an average of 5.5" (139.7mm) of rain in the islands and experiences the highest incidences of thunderstorms and hurricanes in the year. Ponce in the south and Isla Mona in the west are relatively drier than the north and east. Seawater temperatures are the highest of the year in the vicinity of 84°F (28.9°C), but August finds fewer takers for water activities. The sunshine is intense and lasts for a daily 9 hours, even with an almost daily probability of rain. Expect heavy afternoon showers that last for short durations. Shop at the Calle del Cristo when the showers make it challenging to be outdoors. Sun hats and umbrellas are mandatory in August in Puerto Rico at the peak of the hot and wet season.
Weather in September
September is a hot month in the rainy season in Puerto Rico with usually muggy conditions. Mornings and evenings are the best time to visit beaches, swim, walk or relax on the white sands. The probability of rainfall is the highest during the afternoon, which is also the period of stifling hot weather. San Juan registers 5.8" (147.3mm) in September, but the rainiest places are the slopes of the Cordillera Central and the rainforests. Art museums find many connoisseurs in the wet season when it is either too hot or too wet outside. The sun beats the land for 8 hours a day, and it is mandatory to carry sunglasses and hats, as is an umbrella. Expect wind speeds to be at the lowest during the rainy season, and many days see only a light breeze. Expect the heat index to increase with each passing day in September in Puerto Rico.
Weather in October
October reverses the peak heat conditions in Puerto Rico as the temperatures gradually decrease by the end of the month. The day high temperatures average below 88°F (31.1°C), and the nights dip to 76°F (24.4°C). The sunshine lasts for a daily 7.5 hours, and the rays are less intense compared to peak summer. The conditions are still muggy, and it pays to wear sweatshirts and light summer clothing during the day. People love the white sand on the beaches and the warm water that is unlike the cold waters of the North Atlantic. The best times are to visit in the morning or late afternoon after showers that cool the temperatures. Do not discount storm activity and torrential downpour. Keep an eye on the weather for sudden changes. The tourist numbers dwindle in October in Puerto Rico as the precipitation picks up.
Weather in November
November is the wettest month in Puerto Rico with an average of 6.4" (162.6mm) of rain. The average temperatures range between 75°F (23.9°C) to 84°F (28.9°C), and the days are sunny with patches of rain in the afternoons. Heavy rains can cause widespread flooding, and storms can cause significant damage to infrastructure. High tidal waves are frequent during storms along with high-speed winds that cause hotels to shut down due to rough weather. The islands are short of broad-leaf trees in the low-lying areas and offer little shade outdoors when the sun rays are intense. The best bet is to stay indoors during periods of heavy rain. Local history and art museums keep the few visitors busy along with exquisite food when the rain gods are liberal. Expect comfortable temperatures during the night with a drop in humidity. November sees a significant drop in visitor numbers to Puerto Rico.
Weather in December
December is a transitional month in Puerto Rico that sees the reversal of the wet season. The average temperatures are in the 73°F (22.8°C) to 84°F (28.9°C) and see a gradual drop by the end of the month. Puerto Rico hardly has any winter cold due to its tropical location, and cold air from the poles does not travel till the tropics. December still sees 20 wet days and 5" (127mm) of rain, but the cycle decisively shifts towards the dry season. The humidity drops significantly to make the atmosphere pleasant and warm. The daily sunshine is more than 7 hours, but the sun is more like a caring father than a scolding one. Thunderstorms and flash floods last till the end of the year, and an occasional storm still passes over the land. Christmas and New Year's Eve sees many visitors in Puerto Rico due to its warm weather and budget-friendly vacations. The crowds begin to swell in Puerto Rico in December in anticipation of pleasant weather.