Malaysia Weather and Climate
Answer: The principal differences of climate within Malaysia are those arising from difference of altitude and the exposure of the coastal lowlands to the two monsoon regimes, namely, the Southwest Monsoon from late May to September, and the Northeast Monsoon from November to March. Temperatures vary little from month to month, humidity is high, and there is no large daily range of temperature so night-time temperatures are oppressive. Temperatures are distinctly lower in the hills where there are a number of resorts but, although there is little stress from temperature in the hills, the higher humidity, greater rain, and less sunshine offset this benefit.
The Northeast Monsoon brings heavy rainfall, particularly to the east coast states of Peninsular Malaysia and western Sarawak, whereas the Southwest Monsoon normally signifies relatively drier weather. The transition period in between the monsoons is known as the inter-monsoon period.
The northeast monsoon is the major rainy season in the country. Monsoon weather systems which develop in conjunction with cold air outbreaks from Siberia produce heavy rains which often cause severe floods along the east coast states of Kelantan, Trengganu, Pahang and East Johor in Peninsular Malaysia, and in the state of Sarawak in East Malaysia.
The southwest monsoon is comparatively drier throughout the country except for the state of Sabah in East Malaysia. During this season, most states experience monthly rainfall minimum (typically 100 – 150 mm). This is attributed to relatively stable atmospheric conditions in the equatorial region. In particular, the dry condition in Peninsular Malaysia is accentuated by the rain shadow effect of the Sumatran mountain range. Sabah is relatively wetter (exceeding 200 mm) due to the tail effect of typhoons which frequently traverse the Philippine islands in their journey across the South China Sea and beyond.
During the inter-monsoon periods, winds are light and variable. Morning skies are often clear and this favours thunderstorm development in the afternoon. In the west coast states of Peninsular Malaysia, thunderstorms contribute to a mean monthly rainfall maximum in each of the two transition periods.