Mauritius has two seasons: the austral summer (November – April), hot and humid, 28 – 33°C, with a cyclone risk from January to March; and the austral winter (May – October), dry and mild, 22 – 27°C, perfect for hiking and kitesurfing.
The golden rule: the west and north are always warmer and drier than the east and the central plateau. If it rains in Belle Mare, head to Flic en Flac — a 40-minute drive and often 5°C warmer.
Lagoon water stays between 23 and 29°C all year round. For whales and kitesurfing, aim for July – September; for diving and lychee season, November – December.
The word cyclone sounds scary, but the island is among the best prepared in the world. The warning system is simple: class 1 (watch), class 2 (schools closed), class 3 (everything shuts, stay indoors), class 4 (gusts imminent). Hotels are well drilled, buildings are concrete, and an episode rarely lasts more than 24 to 48 hours. Follow the bulletins from the Vacoas weather station (mauritius-meteo.com) and treat it as one more experience — Mauritians use the time to cook a big curry.
Month by month, express version: May – June, mild and green; July – August, windy and cool (pack a jumper, it drops to 16 – 18°C at night on the plateau); September – October, prime hiking time; November – December, rising heat and lychees on every stall; January – March, hot, humid, possible cyclones but gorgeous lagoons; April, golden light and glassy seas. In short: there's no bad season, just different plans.