Weather & Season in Indonesia
Because of its proximity to equator, Indonesia has tropical climate. Generally, the weather is hot and humid. Indonesian climate is divided into two distinct seasons: dry and rainy seasons. Most of Indonesia has their rainy seasons from October through April, but certain places like Maluku have theirs from March to August. During the rainy season, rain starts around noon and lasts into the afternoon. Some areas can have sudden showers for more than two hours.
The dry season does not mean that there are no rains. In fact tropical showers in a dry season's afternoon is a regular affair. The average annual precipitation is 1800 mm. The temperature is almost constant except for the exceptionally rainy season's nights, when it can drop. The temperature on the coast is about 28° C Celsius and drops dramatically in the highlands. For instance, in the highlands of Irian Jaya, temperatures at night can drop to about 7° C, while during daytime they reach to about 22° C.
Upon arrival and disembarking from the plane, you'll immediately notice the sudden rush of warm, wet air. In the highlands temperatures will naturally be cooler, and there are even snow-covered peaks in Papua, whose mountains can soar above 5000 meters. Bring along a jacket if planning to visit eg. Mount Bromo on Java or Tana Toraja in Sulawesi.