The best diving and beach conditions are from December through May, when the northeast monsoon keeps the Sulu Sea calm and visibility underwater can reach 30 metres or more. March and April are the driest months and typically offer the clearest water.
June through November brings the southwest monsoon, with rougher seas and reduced visibility. Some dive sites become inaccessible and boat trips to Sugar Beach can be cancelled when the swell picks up. That said, the worst weather usually passes in a day or two, and experienced divers often find less crowded conditions in the shoulder months of November and December.
Water temperature stays between 27°C and 30°C year-round. The Sulu Sea runs warm even in the rainiest months, so there is rarely any need for more than a 3mm wetsuit.