Sitiawan has a tropical climate — hot and humid year-round with temperatures typically between 25 and 33 degrees Celsius. Rain can fall any time, but the wettest months are October through December. The drier months from January to March are the most comfortable for exploring.
Several festivals add color to the calendar. Thaipusam, the Hindu festival honoring Lord Subramaniam, falls in late January or early February and is celebrated with particular enthusiasm in nearby Pangkor. Ching Ming (Grave-Sweeping Day) in early April sees local Fuzhou families visiting ancestral graves with offerings of paper money, food, and wine. Chinese New Year brings the most festive atmosphere to town, with the date shifting each year according to the lunar calendar.