Climate

There are two seasons in Madagascar: it is hot and rainy from November to April, and cooler and dry from May to October. There is, however, great variation in climate owing to elevation and position relative to dominant winds. Generally speaking, the coast is hotter and wetter (average temperature 21-26°C or 70-80°F) than the plateau (average temperature 13-19°C or 55-67°F).

The climate is tropical along the coast, temperate inland, and arid in the south. The climate of the eastern and north-western coasts is dominated by the south-easterly trade winds that originate in the Indian Ocean anticyclone. These winds carry heavy rains during the austral winter (May to September), averaging as much as 3.5 meters annually.

The central plateau and the western coast are sheltered from the trade winds, but receive rain from the monsoon winds, which blow during the austral summer (October to April). These are a continuation of the Indian monsoons, but produce north-westerly winds and cyclones, coming in principally from the direction of the Mascarene Islands.

Because the rain clouds discharge much of their moisture east of the highest elevations on the island, the central highlands are appreciably drier and, owing to the altitude, also cooler. Thunderstorms are common during the rainy season in the central highlands, and lightning is a serious hazard.

Neither the trade winds nor the monsoons reach the southern part of the island, which consequently receives little rain and is, in places, a semi-desert.