Madagascar, the world’s fourth-largest island, possesses an exceptionally diverse climate. Its immense size, stretching over 1,600 kilometers from north to south, and unique physical geography create a mosaic of environmental conditions. The climate shifts dramatically over short distances, moving from hot, perpetually wet rainforests to cool, temperate highlands and finally to arid, spiny deserts. This complexity means the island spans multiple distinct climate types, influenced by global weather patterns and localized topographical features.
Primary Factors Shaping Madagascar’s Climate
The single most significant factor dictating Madagascar’s climate is the north-south oriented central mountain range. This elevated spine, with peaks exceeding 2,600 meters, acts as a formidable barrier to air masses moving across the Indian Ocean. The island’s position places it directly in the path of the powerful, moisture-laden Southeast Trade Winds, which blow consistently throughout the year.
As these winds approach the eastern coast, they are forced to rise abruptly by the steep mountain slopes, a process known as orographic lifting. The rising air cools, causing the moisture to condense into clouds and fall as heavy, persistent rainfall along the entire eastern facade. This process creates a dramatic rain shadow effect, where the eastern slopes are saturated and perpetually humid. Once the air crests the mountains, it descends the western side, now significantly drier and warmer, creating arid conditions.
During the hot, wet season, the influence of the Inter-Tropical Convergence Zone (ITCZ) and the seasonal northwest monsoon winds also becomes a factor. The ITCZ shifts southward, bringing additional moisture and convective activity to the northern and western parts of the island.
The Four Distinct Regional Climate Zones
The interaction between topography and prevailing winds results in four distinct climatic regions. The East Coast experiences a tropical humid climate, characterized by consistently high temperatures and abundant precipitation year-round. Annual rainfall often exceeds 3,000 millimeters, supporting the island’s lush tropical rainforests with no true dry season. This exposure to constant moisture and heat makes it the wettest region on the island.
The Central Highlands, where the capital Antananarivo is located, is defined by its higher elevation, which creates a temperate or subtropical climate. Temperatures are significantly cooler than the coast, with a distinct cool, dry season from May to October, where nighttime temperatures can drop sharply. Rainfall is moderate, averaging around 1,200 millimeters annually, primarily falling during the hot, wet season between November and April.
Moving to the West Coast, the climate transitions into a tropical dry zone, marked by a clear division between seasons. This region lies in the rain shadow of the central plateau and receives moderate annual rainfall, but experiences a prolonged dry season lasting up to seven months. The vegetation here consists of dry deciduous forests and savanna, adapted to the seasonal lack of water.
The South and Southwest represents the most extreme climate, classified as semi-arid to arid. This region receives the least amount of precipitation, with some areas near Toliara recording as little as 360 millimeters per year. High summer temperatures can push close to 40°C, and the landscape is dominated by the unique spiny forest and thicket.
Annual Cycles and Cyclone Season
Madagascar’s climate operates primarily on two broad seasonal cycles. The hot and wet season runs from November to April, aligning with the austral summer, bringing the highest temperatures and the majority of the annual rainfall. Conversely, the cooler and drier season, corresponding to the austral winter, extends from May to October, offering lower humidity and more moderate temperatures.
The most intense period of weather variability occurs during the hot, wet season, which encompasses the island’s annual tropical cyclone season. This period officially runs from December to April, with the most frequent and severe storms typically occurring between late December and early March. Cyclones form over the warm waters of the Indian Ocean and often track westward, making the eastern coast the most vulnerable region for landfall.
These powerful tropical storms bring destructive winds, storm surges, and torrential rainfall, which frequently lead to widespread flooding and landslides, particularly in the already saturated eastern and northern areas. The recurring nature and significant threat these weather events pose to infrastructure and livelihoods each year is well documented. The western and southern regions are less frequently hit by direct landfall, but they can still experience heavy rains and residual flooding from the storm systems.