on February 10, 2021 
According to the Indonesia’s Meteorological, Climatological, and Geophysical Agency, or BMKG, the wet season is not yet over. In some place, it’s even wetter. Until March, the rainfall is still high. This is caused by several natural phenomenons.
Monsoon
Monsoon changed every six months in a year. For period from October to March is the west monsoon. The wind blows from Asia (north) to south. But before the wind reaches Indonesia, it “stop by” Pacific Ocean and carry clouds filled with water. Hence, when the monsoon reaches Indonesia, the weather is wet and the rainfall is high.
La Nina
During the La Nina, waters off the Pacific Ocean are colder. This tends to lead to heavy rains and clouds to Indonesia, whose waters are warmer. This could lead to more severe rainy season and high rainfall in Indonesia.
Madden-Julian Oscillation
Madden-Julian Oscillation (MJO) is the major fluctuation in tropical weather on weekly to monthly timescales. The MJO can be characterised as an eastward moving ‘pulse’ of cloud and rainfall near the equator that typically recurs every 30 to 60 days. In these months, the clouds are moving from eastern Africa, to South of Indian Ocean, to Pacific Ocean. Hence, crossing Indonesia as well. MJO carries cluster of clouds which will potentially causing heavy rainfall as well.
“What we concern is, if these phenomenons are happening at the same time, overlapping each other. And this will lead to heavy and high rainfall across Indonesia,” Dwikorita Karnawati, head of BMKG, said to CNN Indonesia. We have to be more cautious and careful regarding these months (January to March) wet and rainy season. Stay fit, stay healthy.