Puerto Rico is located in the tropics. Tropical climates are characterized by abundant rainfall and pleasant year-round temperatures that rarely reach into the extremes. Puerto Rico's location makes it prone to violent ocean-born storms.
Puerto Rico's year-round average temperature is around 82 degrees F (28 degrees C); it is slightly warmer on the southern part of the island and slightly cooler in the mountains. For a specific example, in San Juan, Puerto Rico's largest city, the winter and spring months of December through April experience average daily lows of 70 to 72 F (21 to 22 C) and highs of 80 to 82 F (27 to 28 C). The summer and fall months have average daily lows of 73 to 75 F (23 to 24 C) and highs of 85 to 87 F (29 to 30 C). The mountain town of Aibonito experienced Puerto Rico's record high temperature of 99 F (37 C) in 1908.
Precipitation comes in the form of rain in Puerto Rico and is common throughout the year. On average, San Juan experiences 17.6 wet days a month (days with at least 0.01 inches, or 0.25 millimeters, of precipitation). From May through December, rain is common, averaging from 5.4 to 6.3 inches (137 to 160 mm); August and November have the most rain. January and February experience from 4.1 to 4.3 inches (104 to 109 mm), and February and March receive the least rain, with 2.7 to 2.9 inches (69 to 74 mm). Even with the rain, Puerto Rico experiences vast quantities of sun per day.
Humidity is common to tropical climates, and Puerto Rico is no exception. Puerto Rico's humidity is consistent all year. The humidity assists in keeping the temperatures mild. In San Juan, humidity levels range from 74 to 81 percent, changing little throughout the day. The monthly average is approximately 77 percent. In different parts of the island, the level can vary by a marginal degree.
Puerto Rico lies at the heart of the Caribbean corridor. Storms that develop in the Atlantic as far east as the west coast of Africa often make landfall in the Caribbean and the Gulf of Mexico. In general, May through November is the hurricane and tropical storm season. Although Puerto Rico does not get hit directly every year, the storms are a real threat. In 2008, Hurricane Kyle dumped more than 30 inches (762 mm) of rain on the island in a 24-hour period.
