Indonesia's climate is predominantly tropical monsoon. Variations relate mainly to differences in latitude and physical structure, but hilly areas are cooler overall. Rain falls throughout the year, often in thunderstorms, but there is a relatively dry season from June to September. December to March is the wettest period, except in the Moluccas, which receive the bulk of their rain between June and September. Rainfall averages between 60 and 155 inches a year.
