The best time to dive in Cairns and the Great Barrier Reef is from June to November. During these months, several factors create great diving. From June to November, water temperatures drop, attracting a plethora of pelagic species. Manta rays, whale sharks and minke whale all pass through during Australia’s winter. As stated above, water temperatures drop below 77˚F (25˚C). The coldest temperatures occur from July to August when your dive computer might even show 72˚F (22˚C). Like most places, the further you travel from land, the better the visibility becomes. The inner reefs normally have visibility in the 50 feet (15m) range while visibility on the outer reefs is often in excess of 100 feet (30m). If you’re lucky, you might even experience waters as clear as 200 feet (60m). Finally, it should be noted that diving in the Great Barrier Reef from Cairns is also possible from December to May. The weather becomes increasingly hot and rainy, but underwater conditions are still prime for exploration.