The climate in Malaysia remains remarkably consistent throughout the year, with typical daytime temperatures of around 30°.
However, the northeast monsoon brings torrential rains and heavy seas between September and February, concentrating its attentions on the west coast of the Peninsula in September and October, and on the east coast after that.
The ideal time to visit most of the region is between March and early October, when you will avoid the worst of the rains and there’s less humidity, though both ends of this period can be characterized by a stifling lack of breezes.
Despite the rains, the months of January and February are rewarding, and see a number of significant festivals, notably Chinese New Year and the Hindu celebration of Thaipusam.
Visiting just after the rainy season can afford the best of all worlds, with verdant countryside and bountiful waterfalls, though there’s still a clammy quality to the air.
Arrive in Sabah a little later, in May, and you’ll be able to take in the Sabah Fest, a week-long celebration of Sabahan culture, while in Sarawak, June’s Gawai Festival is well worth attending, when longhouse doors are flung open for several days of rice-harvest merry-making, with dancing, eating, drinking and music.