Diving is good all year round, but visibility really takes a drop around late November/beginning of December, where the water changes from blue to green and drops to 27 degrees Celsius. This lasts throughout December till the end of January. In this period visibility is anywhere between 5-10 meters, but can climb to 15 on a good day. The rest of the year expect 15+ meters (up to 30, some say more - but you know how divers are always exaggerating...) The drop in visibility around christmas doesn’t mean that the diving is bad - indeed there are actually more mantas and other pelargics, (who love the extra plankton in the water) they are just more difficult spotting and getting good photos off. If you dream of pygmi seahorses, ornate ghost pipefishes and strange and rare nudibranches - then there’s no reason to shy away from the water. All the magnificent critters are there all year round.