Weather

Madagascar

This large island, a little larger than France, is situated in the Indian Ocean between 12° and 26°S at an average distance of 400 km/128 mi from the African coast. The eastern side of the island is exposed to the moisture-laden southeast trade winds for much of the year. Between November and February, at the time of high sun, the island is affected by the belt of cloud and rain associated with the intertropical convergence. Madagascar is a mountainous island with a steep escarpment rising to 1,200-1,800 m/4,000-6,000 ft behind the east coast. Much of the interior is a plateau above which some isolated, extinct volcanoes rise to heights of 2,100-2,900 m/7,000-9,500 ft. The island slopes down more gradually to the south and west, where there are wider coastal plains.

The whole island has a tropical climate, but above 900 m/3,000 ft temperatures are sufficiently reduced by altitude as to be rarely oppressive or uncomfortable. The lowlands are hot and rather humid, particularly during the rainy season. The east coast is wet for much of the year as it is exposed to the trade winds which are forced to rise as they meet the steep eastward-facing escarpment; see the table for Toamasina, which has an annual rainfall of 3,500 mm/140 in falling on 240 days a year. Most of the east coast receives over 2,000 mm/80 in annual rainfall as does another small area in the northwest around Antsiranana. Rainfall is lower on the interior plateau and decreases to the west and south.

The lowlands in the southwest of the island only receive between 400-800 mm/16 -32 in of rain a year, mostly falling between December and March. The central plateau areas receive an annual rainfall intermediate between these extremes, varying between 1,000 mm/40 in and 1,500 mm/60 in. Most rain here falls between November and March, much of it in heavy downpours associated with hail and thunder. The rainfall during the rest of the year is mostly very light and sporadic (see the table for Antananarivo). On the plateau temperatures fall to moderate levels during the dry season and the nights may be chilly, but frost only occurs on the highest mountains.

Hours of sunshine are quite high around the year even on the wetter east coast. At Toamasina average daily sunshine hours range from six during the cloudier wet months to eight during the drier months. In the drier parts of the island, sunshine hours range from eight to ten hours a day. Apart from the combination of heat and humidity which affects the lower districts of the island during the wet season, the weather and climate of much of the island is sunny, warm, and pleasant for much of the year and this is particularly the case on the plateau.

Two or three times a year some part of Madagascar is affected by torrential rain and high winds associated with tropical cyclones which develop in the Indian Ocean north of the island. These may move southwards either on the western or eastern side of the island and the most damaging effects of their strong winds are felt in the coastal districts.

© Copyright RM, 2007. All rights reserved. Helicon Publishing is a division of RM.

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