Malaysia’s weather is generally hot and sunny all year round, with temperature wavering between 32′C during the day and 24′C at night. Humidity is high at 80 percent. The temperature in cool highlands such as the famous Cameron Highlands and Genting Highlands is slightly lower.
Other than the hot weather and high humidity throughout the year, Malaysia is also affected by two monsoon season, namely the Southwest Monsoon from May to September and the Northeast Monsoon from November to February. The Southwest Monsoon brings with it rain to the west coast of Peninsular Malaysia. The east coast of the peninsular, Sabah and Sarawak experience the Northeast Monsoon which brings heavy rain to the coastal areas during this period.
With this knowledge in mind, it is advisable to avoid visiting the coastal areas during the monsoon period. 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 northeast monsoon is the major rainy season in the country which usually produces heavy rains that often cause severe floods along the east coast states of Kelantan, Terengganu, Pahang and East Johor in Peninsular Malaysia, and in the state of Sarawak in East Malaysia. The transition period in between the monsoons is known as the inter-monsoon period. The inter-monsoon periods experience the heaviest rainfalls and it is considered the rainy season in Malaysia.
The southwest monsoon signifies a drier climate 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.