The dry season, from May to October, is the best time to visit. Temperatures are pleasant — typically 21–27°C — humidity is lower, and the risk of cyclones has passed. This is also when the humpback whales are present, which draws most visitors. July to September is peak season; book flights and accommodation well in advance.
The wet season runs from November to April, with heavier rain, higher humidity, and the real possibility of cyclones between December and April. Travel is still possible — the island doesn't shut down — but flooding can close coastal tracks, and the single weekly flight means disruptions have consequences.
October and early November are a sweet spot: the whales are leaving, the crowds have thinned, accommodation is easier to find, and the weather is still mostly dry. May and June are also pleasant but diving conditions can be rougher than mid-season.