Campbell Bay features a tropical monsoon climate (Köppen *Am* to *Af*), characterized by warm temperatures, high humidity, and abundant rainfall throughout the year. Due to its equatorial location, temperatures remain highly consistent, typically ranging between 23°C (73°F) and 31°C (88°F) year-round.
The town receives heavy precipitation from both the Southwest and the Northeast monsoons, meaning it experiences rain for the majority of the year (often exceeding 3,000 mm annually). There is no distinct dry season, though the months of February to April tend to be slightly less rainy and are considered the best time to visit.
The region is prone to natural disasters, particularly earthquakes, due to its location on the volatile Sunda megathrust fault line. Cyclones are less common this close to the equator but heavy squalls and turbulent seas frequently disrupt sea travel.