Mauritius has two seasons. The dry, cooler winter runs from May to October, with temperatures between 17°C and 26°C, low humidity, and reliable sunshine. The hot, humid summer runs from November to April, with heavier rainfall and the risk of cyclones in January and February.
May to October is the best time to visit. The weather is ideal for hiking, sightseeing, and water sports. July and August are peak season — the island fills with European and South African tourists and prices rise accordingly. If you want good weather without the crowds, May–June or September–October are the sweet spots.
The wet season is not a write-off. Rain tends to come in intense bursts and clear quickly, the sea is warmer, and accommodation is significantly cheaper. Cyclones are possible but rare; if one does approach, the island is well-organised and resorts have evacuation plans.
The southeast trade winds (alizés) blow year-round, keeping the east coast windier and choppier than the west. If you're after calm swimming, the west coast lagoons around Flic en Flac and Le Morne are sheltered regardless of season.
Maha Shivaratri — a major Hindu festival drawing pilgrims from across the island to Grand Bassin — falls in February or March. It's one of the most remarkable spectacles in the Indian Ocean, worth timing your trip around if you're interested in culture.