BMKG Head: Rainy Season to Gradually Start at End of October

By Office of Assistant to Deputy Cabinet Secretary for State Documents & Translation     Date 8 September 2020
Category: News
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Monitoring of days without rain (HTH) per 31 August 2020. (Source: BMKG)

Head of the Meteorology, Climatology, and Geophysics Agency (BMKG) Dwikorita Karnawati has announced that the rainy season in Indonesia will start gradually at the end of October.

It will start from the western part of Indonesia while most parts of Indonesia are predicted to experience the peak of the rainy season in January and February of 2021.

“Most areas are predicted to experience the peak of the rainy season in January and February 2021, with 248 season zones (72.5%),” Dwikorita said through a release received by the editorial of

According to Dwikorita, until the end of August 2020, BMKG monitoring on sea surface temperature anomalies in the equatorial zone of the Pacific Ocean shows the potential for La Nina (index Nino3.4 = -0.69), which has the potential result of increased rainfall in parts of Indonesia during the rainy season.

The arrival of the rainy season is generally closely related to the transition of the Eastern Wind blowing from the Australian Continent (Australian Monsoon) to the Western Wind blowing from the Asian Continent (Asian Monsoon), BMKG Deputy for Climatology Herizal said. He added that the transition of the monsoon winds is predicted to start from the Sumatra region in October 2020, then the Kalimantan region, then parts of Java, Bali, Nusa Tenggara in November 2020, and finally the Asian Monsoon is fully dominant in the Indonesian territory from December 2020 to March 2021.

Of the total 342 season zones in Indonesia, 34.8% are predicted to start the rainy season in October 2020, namely in parts of Sumatra, Java, Kalimantan, and Sulawesi. As many as 38.3% of the area will enter the rainy season in November 2020, covering parts of Sumatra, Java, Nusa Tenggara, Kalimantan, Sulawesi, Maluku, and Papua. Meanwhile, the rest of 16.4% covering parts of Java, Kalimantan, Sulawesi, Maluku, West Nusa Tenggara, East Nusa Tenggara, and Papua will enter the beginning of the rainy season in December 2020.

When compared to the climatological average at the beginning of the rainy season (1981-2010 period), the beginning of the 2020/2021 rainy season in Indonesia is predicted to be late in 154 season zones (45%), normal in 128 season zones (35%), and ahead of time in 68 season zones (20%).

Furthermore, when compared to the climatological average of rainfall accumulation in the rainy season (1981-2010 period), in general, the conditions for the 2020/2021 rainy season are predicted to be normal or the same as the climatological average in 243 season zones (71%). However, a total of 92 season zones (27.5%) will experience above normal rain conditions (Wetter Rainy Season), such as the rainy season rainfall is higher than the climatological average and 5 season zones (1.5%) will experience the below normal season (Dryer Rainy Season) such as rainfall that is lower than the average.

Furthermore, Dwikorita emphasized the need for vigilance as well as early and optimal preparation for mitigation efforts by stakeholders and local governments whose areas are predicted to experience a more advanced or wetter rainy season.

“This mitigation is carried out by implementing integrated water management from upstream to downstream, among others by filling and storing water into lakes, reservoirs, retention basins, retention ponds, and other artificial water storage, as well as preparing the capacity of rivers and canals to anticipate the discharge of excess water,” read the release. (PR of BMKG/EN).



Translated by: Fairuzzamani Inayatillah
Reviewed by: Yuyu Mulyani

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