These are the "shoulder seasons." The weather is unpredictable but generally characterized by calm seas in the morning and heavy thunderstorms in the late afternoon or evening.
The East Coast of Peninsular Malaysia (Kelantan, Terengganu, Pahang, and Eastern Johor), Western Sarawak, and Northeastern Sabah. when is monsoon season in malaysia
If you are seeking sun and islands, the "bad" season is November to March for the East Coast of the Peninsula and Western Borneo. These are the "shoulder seasons