Like most parts of Southeast Asia, Melaka is hot and humid year round with temperatures ranging from 21 to 32 degrees Celcius. Rainfall is significant throughout the year though not bearable and there is seldom any flooding.
Pack as you would for a tropical city tour and throw in good walking shoes, a jacket for drafty evenings and an umbrella.
Do remember to cover up decently when visiting places of worship, especially mosques in accordance with Malaysian traditions and customs.