Climate Réunion
With its lagoon-protected seashores, primary jungles, savannah slopes and 3,070 m peak, the island's multiple landforms give rise to over two hundred microclimates. Mountain climate towards Dimitile, hot and dry tropical climate towards Saint-Gilles, hot and humid tropical climate towards Saint-André, temperate and cool in the cirques. So it's almost impossible to rely solely on the weather forecast, which only gives you the broad outlines. However, if you're planning a long hike, it's a good idea to check for heavy rain and possible cyclone and thunderstorm warnings. For the rest, it's best to get out as soon as the weather's fine, as it can change rapidly. The advantage of this is that if it rains where you are, you can often just drive a few kilometers to get back to fine weather.
The windward coast and the leeward coast
Like most islands in the southern hemisphere, Réunion has a marked contrast between its green, rainy east coast and its arid, dry west coast. The east coast is known as the "windward coast", swept by the trade winds from the east and southeast, which bring with them their share of rain, creating a lush, green landscape unaffected by the changing seasons. Conversely, the west coast, known as the "leeward coast", receives very little rain, except in its higher elevations, and presents savannah-like landscapes adorned with yellow and red hues reminiscent of the sweltering heat of the south in summer. Two coasts, two universes, which has enabled tourism to diversify: in the west, seaside resorts attract travellers looking for rest and relaxation with their feet in the water, while the much wilder east is more focused on river activities - canyoning, fishing, swimming, hiking, climbing waterfalls - and discovering the abundant vegetation.
The freshness of the heights
While it's always warm in the lower reaches, rarely below 25°C during the day all year round, whether to the east or west, it can quickly become cool or even cold in the higher elevations, with temperatures dropping by around 8°C every 1,000 m. Don't forget that it can snow or frost on the volcano, Piton des Neiges or Col des Bœufs in winter. While this may frighten the sun-seeking tourist, many locals have abandoned the year-round Bas for the mid-slopes, where every house has a fireplace and falling asleep under a thick comforter is a real pleasure. As far back as the 19th century, the bourgeoisie owned their second homes at altitude (the famous "change of air") to escape the stifling promiscuity of the Bas. So always remember to bring a sweater and appropriate clothing if you're going to the mountains. Note that in the rainy season, the Hauts tend to be covered in clouds and fog very early in the day (around 10 a.m.), blocking the view until late afternoon. To take advantage of the wonderful panoramic views, it's best to start your hike at sunrise and then head to the beach at the end of the day for a nap in the warmth of the sand.
Rainy season and dry season
Reunion doesn't have the four seasons of mainland France, but rather two long, distinct seasons: the dry season from April to November and the rainy season from December to March. Each has its own advantages: the dry season is generally sunny all day long. The air temperature hovers around 27°C along the coast, the weather is fine, and the climate is ideal and pleasant, ventilated by the gentle breeze of the trade winds. Evenings are cool, however, especially in the Hauts and mountains, where gloves and scarves are a must in the evenings and mornings. July to September is also whale-watching season, an unforgettable spectacle. However, the sea is rougher, with the southern swell creating large waves that are beautiful to look at but a deterrent to swimming, and the water temperature drops to 20-25°C. Dry-season trips are therefore more likely to involve cultural activities, hikes and boat trips than lazing on the beach.
In the wet season, from December to March, temperatures rise to 30°C, with peaks of 35-40°C in certain regions such as Le Port and Saint-Paul. The sea then rises to 27-28°C, and you could easily spend the day lounging in the water. While this heat can be oppressive, don't forget that the austral summer is still the best time to boycott the winter cold of mainland France! November and December also see the flowering of many colorful trees, such as the red flamboyant and the purple jacaranda, and the arrival of "tropical" fruits on the markets: passion fruit, mango and, above all, letchis! These little delights alone are reason enough to travel. On the other hand, as its name suggests, the wet season is also characterized by more frequent rains and very changeable weather, which sometimes compromises hiking and mountain outings. It's also the cyclone season.
Random cyclones
While tourists dread the arrival of cyclones because of the plane cancellations and heavy rain they bring, locals tend to look forward to their arrival to "refresh the vegetation". And with good reason, since Reunion Island is on the "classic" path of Indian Ocean cyclones. The numerous storms and depressions that plague the humid, heavy, humidity-saturated southern summer are considered cyclones when their winds exceed 117 km/h. The term "intense tropical cyclone" is used to describe a storm of varying degrees of violence. Intense tropical cyclones" are defined as those reaching 166 km/h, and "very intense tropical cyclones" as those exceeding 213 km/h. All of these powerful gusts, which can reach speeds in excess of 300 km/h, are invariably accompanied by torrential rainfall: up to 2,200 mm of water can fall in 24 hours. The barometer plummets, the swell rages, and everyone locks themselves in their homes after having rushed to the supermarkets to stock up on provisions as soon as the first warning is issued. Although, thanks to the quality of weather forecasts and current infrastructures, "gales" now claim very few victims, they often cause considerable material and natural damage: power cuts, flooding, deterioration of roads, destruction of buildings, bridges and forests... In January 2024, with winds exceeding 250 km/h, cyclone Belal caused four deaths and considerable damage (42,000 claims recorded). Météo France keeps a close watch and issues alerts as the disturbance develops. Some cyclones circle the island for more than a week before dissipating or moving away. And after a cyclone has passed, the dangers are still numerous: roads cut off, gullies overflowing, furious swells, etc. The unexpected is also part of the trip, but everything is well orchestrated: you just have to be vigilant and informed.
