The rule
Section 3 of the Holidays Act 1951 (Act 369): when a public holiday falls on the weekly rest day (Sunday, or Friday in states where Friday is the weekly rest day), the next day is a public holiday instead, and if that day is already a public holiday, the day after it. A state, or the Minister for the Federal Territories, can provide otherwise by notice in the Gazette.
Kedah, Kelantan and Terengganu rest on Friday and Saturday, so a Sunday holiday is not replaced there, and the Act would move a Friday holiday to the Saturday. Their replacement days are set by each state; the ones shown for them are not yet confirmed from an official source, so check the state government's announcement.
Sabah and Sarawak have their own holiday ordinances, which we have not yet read; their replacement days here assume the same Sunday rule, and stay unconfirmed until announced.
Sources: Federal public holiday table 2027 (Prime Minister's Department) and Akta 369, section 3 (Attorney General's Chambers text).
All public holidays 2027 →