GENERAL CLIMATE OF MALAYSIA

		Introduction
		Wind flow in Malaysia
		Rainfall Distribution
		Seasonal Rainfall Variation in Peninsular Malaysia
		Seasonal Rainfall Variation in Sabah and Sarawak
		Temperature Distribution
		Relative Humidity
		Sunshine and Solar Radiation
		Evaporation

Introduction

The characteristic features of the climate of Malaysia are uniform temperature, high humidity and copious rainfall and they arise mainly from the maritime exposure of the country. Winds are generally light. Situated at the equatorial doldrum area, it is extremely rare to have a full day with completely clear sky even in periods of severe drought. On the other hand, it is also rare to have a stretch of a few days with completely no sunshine except during the northeast monsoon seasons.

Wind flow in Malaysia

Though the wind over the country is generally light and variable, there are, however, some uniform periodic changes in the wind flow patterns. Based on these changes, four seasons can be distinguished, namely, the southwest monsoon, northeast monsoon and two shorter intermonsoon seasons.

The southwest monsoon is usually established in the later half of May or early June and ends in September. The prevailing wind flow is generally southwesterly and light, below 15 knots.

The northeast monsoon usually commences in early November and ends in March. During this season, steady easterly or northeasterly winds of 10 to 20 knots prevail. The more severely affected areas are the east coast states of Peninsular Malaysia where the wind may reach 30 knots or more during periods of intense surges of cold air from the north (cold surges).

The winds during the two intermonsoon seasons are generally light and variable. During these seasons, the equatorial trough lies over Malaysia.

It is worth mentioning that during the months of April to November, when typhoons frequently develop over the west Pacific and move westwards across the Philippines, southwesterly winds over the northwest coast of Sabah and Sarawak region may strengthen reaching 20 knots or more.

As Malaysia is mainly a maritime country, the effect of land and sea breezes on the general wind flow pattern is very marked especially over days with clear skies. On bright sunny afternoons, sea breezes of 10 to 15 knots very often develop and reach up to several tens of kilometer inland. On clear nights, the reverse process takes place and land breezes of weaker strength can also develop over the coastal areas.