Indonesia has two main seasons: rainy and dry. The dry season is from April to October, while the rainy season is from November to March. Yet, it is becoming more unpredictable nowadays because of the global warming. Winds are moderate and generally predictable, while monsoons usually blow in from the south and east between June and September and from the northwest between December and March.

Temperature slightly varies from season to season, but remain fairly constant, with the coastal plains averaging 28°C, the inland and mountain areas averaging 26°C, and the higher mountain regions, 23°C. Indonesia experiences relatively little change in the length of daylight hours from one season to the next.

In general, the temperature drops approximately 1°C per 90-meter increase in elevation from sea level with some high-altitude interior mountain regions experience night frosts. The humidity level changes depending on the rainfall, ranging from 70% to 90%.