The Marquesas do not have a conventional rainy season in the way that Tahiti does. The dry season runs roughly from June to October, with more reliable weather for hiking and inter-island boat travel. The wet season brings heavy but intermittent rain, and some tracks become impassable.
The Marquesas Festival of Arts (Matavaa) takes place every four years, bringing performers from across the archipelago together for traditional dance, music, tattooing, and craft demonstrations. It is a remarkable event — one of the most vivid survivals of traditional Polynesian culture — and worth timing a visit around if you can. Check the current year's schedule well in advance, as accommodation on the islands fills completely.