The hottest month in Puerto Rico is September when the average maximum temperature is 32°, average temperature is 28° and average minimum temperature is 25°.
The coolest month in Puerto Rico is January when the average maximum temperature is 28°, average temperature is 25° and average minimum temperature is 22°.
The longest days in Puerto Rico are in June, with an average of 13.2 hours of daylight per day. December has the shortest days with an average of 11 hours of daylight per day.
The sunniest days in Puerto Rico are in August which has the most hours of sunshine per day with an average of 9.1 hours of sunshine per day, making it a sunny month with few clouds. March has the least sunshine with an average of 5 hours of sunshine per day, making it a sunny month that is overcast at times.
The ultraviolet index is the highest in April when it reaches 13.6 and lowest in December when it reaches 7.6.
An ultraviolet index reading above 11 indicates an extreme risk of harm from unprotected sun exposure. Unprotected skin risks burning in less than 10 minutes. Take all precautions because unprotected skin and eyes can burn in minutes. Tanning will be safest before 10am and after 4pm but only with a good application of sun screen. For those with sensitive skin stay in the shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days. Watch out for relections from water that may increase ultraviolet exposure.
The warmest sea water temperatures in Puerto Rico are found in September when they peak at 29° and lowest in February when they dip to 26°.
The sea is excellent for swimming all year round as the water temperature is very warm and ideal for relaxing and swimming for the whole day.
The wettest month in Puerto Rico is May with 41.2cm of rain and July has the most days of rain with 17.6 days with some rain, a wet time to visit the beach.
The driest month in Puerto Rico is February with 8.5cm of rain and March has the fewest days of rain with 11.9 days with some rain, a slightly wet time to visit the beach.
The most humid month in Puerto Rico is August with a dew point (an indicator of humidity) of 25° which is very uncomfortable and fairly oppressive unless you are on a beach. At night you would most likely require airconditioning.
The least humid month in Puerto Rico is February with a dew point of 22° which is very humid and quite uncomfortable for most unless you are on a beach. At night you would most likely require a fan.
The most windy month in Puerto Rico is July when the average maximum windspeed is 25kmh and the average wind speed is 12kmh.
The least windy month in Puerto Rico is September when the average maximum windspeed is 22kmh and the average wind speed is 9kmh.