The hottest month in Hanalei Bay Beach is September when the average maximum temperature is 29°, average temperature is 27° and average minimum temperature is 23°.
The coolest month in Hanalei Bay Beach is January when the average maximum temperature is 26°, average temperature is 22° and average minimum temperature is 19°.
The longest days in Hanalei Bay Beach are in June, with an average of 13.5 hours of daylight per day. December has the shortest days with an average of 10.8 hours of daylight per day.
The sunniest days in Hanalei Bay Beach are in April which has the most hours of sunshine per day with an average of 8.4 hours of sunshine per day, making it a sunny month with few clouds. December has the least sunshine with an average of 5.1 hours of sunshine per day, making it a sunny month that is overcast at times.
The ultraviolet index is the highest in July when it reaches 12.9 and lowest in December when it reaches 6.2.
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 Hanalei Bay Beach are found in September when they peak at 28° and lowest in February when they dip to 24°.
The sea is best for swimming between May and December when the temperature is above 26° which is warm and pleasant for relaxing and swimming for long periods.
The wettest month in Hanalei Bay Beach is March with 22cm of rain and June has the most days of rain with 24.7 days with some rain, a very wet time to visit the beach.
The driest month in Hanalei Bay Beach is June with 4.2cm of rain and May has the fewest days of rain with 18.1 days with some rain, a wet time to visit the beach.
The most humid month in Hanalei Bay Beach is August with a dew point (an indicator of humidity) 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 least humid month in Hanalei Bay Beach is February with a dew point of 19° which is somewhat uncomfortable for most people in cities but fine on a beach.
The most windy month in Hanalei Bay Beach is March when the average maximum windspeed is 34kmh and the average wind speed is 22kmh.
The least windy month in Hanalei Bay Beach is May when the average maximum windspeed is 30kmh and the average wind speed is 19kmh.