Indonesia has some of the planet’s highest seismic and volcanic activity, so natural disasters such as eruptions, earthquakes and tsunamis are constant threats. The most famous of these is the Krakatoa explosion of 1883, which destroyed many nearby villages and caused a sonic boom that was heard as far away as Mauritius off the coast of Africa. More recent disasters include the large earthquake and tsunami that hit southeast Asia in December 2004, and another earthquake in the village of Yogyakarta in May of 2006. Currently, the Mt. Merapi volcano on the island of Java is exhibiting a lot of activity. An eruption may come at any time, so be prepared for an evacuation.

Jakarta’s climate is tropical and humid almost year-round; as it is so close to the equator, average temperature is almost exactly the same in January and July at about 82°F (28°C). Variation throughout the day is minimal as well, with low temperatures around 76°F (24°C) and highs of 88°F (31°C). Rainfall is moderate except for the winter months, when it becomes very heavy due to monsoon season. As the city is below sea level, the canal system designed to drain the city of excess water is sometimes overwhelmed, and parts of the city are under water for days after a heavy rain. It is best to avoid Jakarta between December and March unless you are prepared to sightsee in galoshes.

A chart of monthly averaged statistics for temperature and rain can be found on this Jakarta Weather Page.  It also has the up-to-the-moment weather information from the weather station at Jakarta's Soekarno-Hatta International Airport.