The hottest month in Grand Cayman is August when the average maximum temperature is 32°, average temperature is 29° and average minimum temperature is 27°.
The coolest month in Grand Cayman is January when the average maximum temperature is 28°, average temperature is 26° and average minimum temperature is 24°.
The longest days in Grand Cayman are in June, with an average of 13.3 hours of daylight per day. December has the shortest days with an average of 11 hours of daylight per day.
The sunniest days in Grand Cayman are in February which has the most hours of sunshine per day with an average of 7.8 hours of sunshine per day, making it a quite sunny month with some cloud cover. October has the least sunshine with an average of 5.9 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 13.4 and lowest in December when it reaches 7.2.
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 Grand Cayman are found in September when they peak at 30° and lowest in February when they dip to 27°.
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 Grand Cayman is August with 2.8cm of rain and October has the most days of rain with 15.3 days with some rain, a wet time to visit the beach.
The driest month in Grand Cayman is March with 0.1cm of rain and February has the fewest days of rain with 5.2 days with some rain, a dry time to visit the beach.
The most humid month in Grand Cayman is August with a dew point (an indicator of humidity) of 27° which is extremely humid and uncomfortable unless you are on a beach. At night you would most likely require airconditioning.
The least humid month in Grand Cayman is January with a dew point of 23° 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 Grand Cayman is November when the average maximum windspeed is 28kmh and the average wind speed is 19kmh.
The least windy month in Grand Cayman is September when the average maximum windspeed is 21kmh and the average wind speed is 11kmh.