Weather and Climate in Puerto Rico

Weather and Climate in Puerto Rico

The mountains of the Cordillera Central are the main cause of the variations in the rainfall and temperature that occur over only very short distances in Puerto Rico, particularly in inland areas. The mountains can also cause wide variation in local wind speed and direction due to their sheltering and channeling effects.

Most of Puerto Rico's rainfall is orographic in nature. Moisture laden air is carried by wind and forced to ascend over the mountains. The rise in elevation cools the air, causing condensation in the form of rain.

The trade winds that come from east to west across the island from the Atlantic bring most of the rain that falls from May to November. Depending on their intensity and speed, these winds can produce little more than a few clouds to several days of cloudy and rainy weather, and occasionally hurricanes. Most rain falls as the wind rises over and along the east-west mountain axis. More rain falls on the Luquillo mountains in the eastern part of the divide than the western part because the moisture laden air first ascends in the east. The northern slopes of the divide also receive more rainfall than the southern slopes because their gradual rise to the peaks serves as a great catchment area. The southern slopes tend to descend more abruptly to the sea.

The other rain period occurs during winter months from November to April. Because Puerto Rico is in the seasonal tropics it is susceptible to cold fronts that can sweep south across the continental United States. These fronts can bring rain particularly to the northeastern part of the island. Occasionally fronts are strong enough to penetrate across the whole island bringing with them several days of rain.

Apart from these two main rainfall processes, rain occurs as local showers and thunderstorms. This happens during periods of hot weather when the land heats up more quickly than the sea. The heated air over the land rises and is replaced by cool air that rushes in over the land as onshore winds. The heated air cools as it rises over the mountains and gives rise to afternoon clouds and often to rain. Rainfall is lowest in the south and southwest parts of the island because of the rain shadow effect of the mountain divide.

Mean temperatures in Puerto Rico vary little between the warmest and coldest months. The smallest ranges are near the coast where daily and monthly temperature variation is tempered by the sea. Monthly mean temperatures on the northern coast vary between about 80 degrees in August, the warmest month, to 75 degrees in January and February, the coolest. Further inland slightly larger ranges are observed and hotter and colder mean monthly temperatures occur. Daily temperature fluctuations reflect the same patterns with ranges between 10-15 on the northern and eastern coasts, increasing to between 15-20 further inland. In the drier south and southwest changes may fluctuate 15-20 or more. In the south, temperatures may reach greater than 90 F for more than 200 days of the year. Freezing temperatures are unknown in Puerto Rico though many montane areas experience temperatures in the 40s.

To check the current weather condition of Puerto Rico please click here

SouthTravels.com
Copyright © Southtravels.com. All Rights Reserved.