End of Year Weather Unpredictable, Beware of High Waves and Heavy Rain

JAKARTA - The Meteorology, Climatology and Geophysics Agency (BMKG) urges the public to increase vigilance ahead of the 2025 Christmas and 2026 New Year celebrations as the potential for rainfall increases in a number of regions in Indonesia. This condition is influenced by the active Asian monsoon which brings a supply of wet air mass from the Asian region to the Indonesian region.

BMKG Public Meteorology Director Andri Ramdhani said that an increase in rainfall is common in the climatological period from late December to early January.

"In the period leading up to Christmas, especially the third week of December to early January, there is indeed an increase in rainfall in terms of climatology," Andri said at a press conference in Jakarta, Tuesday, December 23.

BMKG noted that the areas that needed more attention included southern Sumatra, including Bengkulu, Jambi, South Sumatra, and Lampung, then Java, Bali, Nusa Tenggara, South Papua, and parts of South Sulawesi and Maluku.

Andri urged the public to remain calm but vigilant against the potential for extreme weather that could occur at any time, such as heavy rain, strong winds, flooding, landslides, and high waves, especially in disaster-prone areas, hilly areas, and coastal areas.

He also asked the public to be more careful in planning activities during the Christmas and New Year holidays, including land, sea, and air travel, as well as outdoor activities such as worship, tourism, and New Year's Eve celebrations.

BMKG is also monitoring the presence of Tropical Cyclone Grant which is the development of the 93S tropical cyclone seed. However, Andri ensured that the cyclone did not have a direct impact on the Indonesian region.

"The Grant Tropical Cyclone is moving away from the Indonesian region, so it does not have a direct impact on weather conditions in Indonesia," he said.

However, the movement of the cyclone increases wind speed and wave height in a number of waters, especially in the west of Bengkulu, Lampung, south of Banten, including the southern Sunda Strait crossing area, as well as the southern waters of Java from Banten, West Java, Central Java, DI Yogyakarta, to East Java.

For the next week, BMKG predicts that rain is still potentially raining in Aceh, North Sumatra, and West Sumatra with a light intensity, namely less than 20 millimeters per day. Several areas in Aceh are expected to experience moderate rain.

"There are several districts in Aceh that are in the yellow category, which means moderate rain. However, in general, the conditions in the Aceh region are still relatively conducive for the next week," said Andri.

Similar conditions are also expected in North Sumatra and West Sumatra, with a relatively conducive weather pattern, although there are certain regions and times that need to be aware of the potential for moderate to heavy rain.

"In general, the three affected provinces in the next week are in a relatively conducive condition," he said.

Andri added that this condition was also supported by the implementation of weather modification operations carried out together with the National Disaster Management Agency (BNPB). BMKG, he said, will continue to monitor the very dynamic atmospheric dynamics.

"If there are significant changes, weather modification operations will be activated to reduce the intensity of the rain so that the recovery process in the field is not hampered by the weather," he concluded.