Lying just south of the equator, the Seychelles islands have a tropical climate, with warm and humid weather influenced by the trade winds. The islands can be visited all year around, with April often regarded as the very best month.
From October until April the light warm northwest winds bring short sharp rain. This is the best time for marine activities as the seas are at their calmest, with excellent visibility for snorkelling, diving & fishing.
December and January are usually the wettest months, but severe storms are rare as the Seychelles islands lie outside the cyclone belt.
From May the winds change direction and the southeast trade winds bring dry and slightly cooler weather until September, with fresh breezes. The seas can be a little choppy when these winds are at their peak in July and August.
Seasonal seaweed can affect Praslin in particular, but as there are beaches on both sides of the island you can book a hotel on the correct coast, according to the season (or simply travel to the beaches not affected, as distances are short). From October to March the east beaches are best. From April to September the west beaches are best.