Located in the equator, Indonesia climate is composed of two seasons: dry and rainy seasons, each lasts for about 6 months. These two seasons used to be predictable, dry season starts in April, when the sun is in the north, until September. Then the rainy season starts at the end of September until April. But now it is hard to predict when these seasons start and end, due to the global warming.
Since Indonesia is an archipelago and located between two continents, Indonesia climate is very much affected by the climate of Asia and Australia. During fall and winter in Asia, the cold winds blow from Asia in the north, passing Indonesia to Australia. Likewise, during fall and winter in Australia, the cold winds blow from Australia in the south through Indonesia to Asia. That’s when our season changes, from dry season to rainy season, and vice versa.
We also expose to global warming. Nowadays there are many storms occur all around the earth. Sometimes the wind pushes the storm from Taiwan, China, Philippines or Australia to Indonesia in the form of heavy rain and flood in some regions. Or some whirlwinds pass by, which rarely occurred in the past.
Nevertheless, the temperature in Indonesia is relatively stable, since we only experience two seasons, It’s around 30 degrees Celsius during the day then drop to 20s Celsius at night. The temperature also depends on the location, how high it is from the sea level. For example, being in the north coast of Java, Jakarta is warmer, the temperature can reach 35 degrees Celsius, sometimes accompanied by hot winds. On the other hand, being in the highlands, Puncak is cooler with cool winds blowing, a perfect location for tea plantations.
Don’t you think it’s like summer all year long? I think so too, except for the humidity. The humidity in Indonesia is high, more than 90%. Sometimes it reaches 99% for a place like Bandung, being in a valley and surrounded by mountains.
Nowadays Indonesia climate is unpredictable, it is hard to say when is the dry season or rainy season, and no one can guarantee there will not be any rainfall during dry season. Thus, you’d better bring a raincoat or small umbrella when you travel Indonesia.
Most of you will feel warm all the time, especially when you come from four seasons countries. Therefore, it’s better you wear some light clothes and bring a jacket for cool evenings or when you go to highlands where the cool winds blow.
Please remember to use proper clothing when you enter religious places, such as temple, church, mosque, etc. Proper clothing means no tank top or short pants. Some temples provide sarong or a piece of long cloth to be tied on your waist as a belt so you can enter the sacred place properly.
So, if you plan to travel Indonesia or explore Sunda, I hope this information on Indonesia climate helps you prepare for the journey.