The hottest month in St Martins is July when the average maximum temperature is 19°, average temperature is 17° and average minimum temperature is 15°.
The coolest month in St Martins is February when the average maximum temperature is 9°, average temperature is 8° and average minimum temperature is 7°.
The longest days in St Martins are in June, with an average of 16.3 hours of daylight per day. December has the shortest days with an average of 8.1 hours of daylight per day.
The sunniest days in St Martins are in June which has the most hours of sunshine per day with an average of 8.7 hours of sunshine per day, making it a sunny month with few clouds. December has the least sunshine with an average of 1.9 hours of sunshine per day, making it not a particularly sunny month.
The ultraviolet index is the highest in June when it reaches 7.7 and lowest in December when it reaches 0.6.
An ultraviolet index reading of 8 to 10 indicates a very high risk of harm from unprotected sun exposure. Unprotected skin risks burning in less than 15 minutes. Take extra precautions because unprotected skin and eyes will be damaged and can burn quickly. 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 St Martins are found in August when they peak at 17° and lowest in March when they dip to 10°.
The sea is best for swimming between June and December when the temperature is above 13° which is very cold and bracing, it's not recommended you swim with out a full wet suit.
The wettest month in St Martins is November with 1.6cm of rain and October has the most days of rain with 13.2 days with some rain, a slightly wet time to visit the beach.
The driest month in St Martins is July with 0.5cm of rain and May has the fewest days of rain with 9.6 days with some rain, a dry time to visit the beach.
The most humid month in St Martins is July with a dew point (an indicator of humidity) of 15° which is comfortable for everyone.
The least humid month in St Martins is February with a dew point of 6° which is a bit dry for some.
The most windy month in St Martins is December when the average maximum windspeed is 41kmh and the average wind speed is 32kmh.
The least windy month in St Martins is July when the average maximum windspeed is 29kmh and the average wind speed is 21kmh.