Saint Lucia has two seasons: a dry season from December to May and a wet season from June to November. The climate is tropical and warm year-round, with temperatures ranging between 24°C and 32°C (75–90°F).
December to April is peak season. The weather is dry and breezy, humidity is lower, and rainfall is rare. It is also the most expensive time to visit and can be crowded, particularly around Christmas, New Year, and February. Book accommodation well in advance if you're travelling in this window.
May and June are a good compromise. The dry season is ending, crowds have thinned, prices are lower, and the island is still in good shape. The Jazz & Arts Festival takes place in May and is worth timing your visit around if you're interested in it.
July to November is hurricane season. Saint Lucia sits in the hurricane belt and can be directly affected, though it has been relatively lucky compared to some neighbouring islands. Rain comes in heavy short bursts rather than all-day downpours, and many days are fine. Hotels offer significantly discounted rates during this period.
October is worth considering if you want to see Saint Lucia's culture at its most vibrant. The Jounen Kwéyòl festival on the last Sunday of October is one of the island's biggest celebrations, with villages across the island hosting food, music, and cultural events.
The rainforest is most lush during and just after the wet season. If hiking and birdwatching are your priorities, the period between September and November can actually be rewarding, weather risks aside.