The longest days in Lord Howe Island are in December, with an average of 14.2 hours of daylight per day. June has the shortest days with an average of 10.1 hours of daylight per day.
The sunniest days in Lord Howe Island are in January which has the most hours of sunshine per day with an average of 4.7 hours of sunshine per day, making it a sunny month that is overcast at times. May has the least sunshine with an average of 2.5 hours of sunshine per day, making it not a particularly sunny month.
The ultraviolet index is the highest in January when it reaches 14.1 and lowest in June when it reaches 3.1.
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 Lord Howe Island are found in January when they peak at 25° and lowest in July when they dip to 19°.
The sea is best for swimming between December and April when the temperature is above 22° which is comfortable for swimming though some may prefer warmer water.