Weather

Myanmar

Myanmar, formerly Burma, is rather larger than France. This Southeast Asian country has a long mountain-backed coastline on the Bay of Bengal and a long southeastern border with Thailand and Laos. It borders India and Bangladesh on the northwest, and China on the northeast; this is a very mountainous region which includes part of the eastern Himalayas and the edge of the mountain plateau of Yunnan in southern China.

Much of Myanmar is mountainous, with the main mountain and hill ranges running from north to south. The highest regions in the north rise to over 5,500 m/18,000 ft, but the average height of the mountains elsewhere is 1,200-2,400 m/4,000-8,000 ft. The centre of the country north of Mandalay to the coast at Yangon is a lowland area in which flow the great rivers Irrawaddy and Salween. They rise in the high mountain region of the north where rainfall is heavy. Most of the eastern border with Thailand runs through a high plateau region when rainfall is also heavy.

Myanmar has a tropical monsoon type of climate with a marked difference between a cooler, dry season from November to April and a hotter, wet season from May until September or October. This seasonal contrast is a result of the great reversal of winds which occurs over south Asia. As in India, the dry season is dominated by the northeast monsoon blowing overland from China. Differences of altitude within Myanmar, and the degree of exposure to the rainy southwest monsoon, are responsible for the main differences of climate within the country.

The coastal mountains and the higher mountains of the north and east have abundant or heavy rainfall which ranges from 2,500 mm/100 in to 5,000 mm/200 in a year. The interior lowlands, sheltered from the direct effect of the southwest monsoon, receive as little as 1,000 mm/40 in or even less (see the table for Mandalay). Over most of the country at least three-quarters of the annual rainfall occurs during the season of the southwest monsoon.

In the lowlands, and particularly on the coast, temperatures are hot throughout the year. The highest temperatures occur during the period March to May before the onset of the heaviest rains. Temperatures are lower in the hills, but for most of the year the weather at places below 1,200 m/4,000 ft can be described as hot and tropical. The table for Lashio is representative of places inland at medium heights. On the coast the high temperatures are rendered more unpleasant because of high humidity. Even inland the heat is oppressive during the rainy season for the same reason (see the table for Mandalay).

The dry season is distinctly cooler and more pleasant in the interior and particularly in the north of the country where increasing altitude lowers the temperature. The period from November to April is distinctly dry over the whole country. At this time, when the country is dominated by the dry northeast monsoon, sunshine amounts are high, averaging from seven to ten hours a day. During the rainy season the weather is much cloudier and from June to September daily sunshine amounts average only three to four hours a day.

Climatic conditions on the wettest parts of the coast are illustrated by the table for Sittwe. The table for Yangon (formerly Rangoon) shows that here, on the delta of the Irrawaddy where the coast runs from west to east and is low-lying, rainfall is less but temperature and humidity remain high throughout the year.

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

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