BMKG warns of rain and strong winds in North Sumatra

The Meteorology, Climatology and Geophysics Agency (BMKG) is urging the public to remain vigilant for potential rain accompanied by strong winds and lightning in parts of North Sumatra on Sunday (21/6).

BBMKG Region I forecaster Budi Prasetyo in Medan stated on Saturday that several areas in North Sumatra still have the potential for rain on Sunday, which must be watched out for as it may be accompanied by lightning and strong winds.

“Be alert to the potential for moderate to heavy rain that can be accompanied by lightning and strong winds in the southern region, eastern slopes, and east coast of North Sumatra, which can cause disasters such as floods and landslides,” he said.

In detail, the weather in North Sumatra on Sunday morning has the potential for light rain in South Nias and surrounding areas. In the afternoon to evening, there is potential for light to moderate rain evenly across almost all areas of North Sumatra, and in the early hours, light rain is possible in Padang Lawas, North Padang Lawas, Mandailing Natal, South Nias, and surrounding areas.

Average temperatures range from 14 to 33 degrees Celsius, with humidity between 67 and 99 percent, and winds blowing from the South to Southwest at speeds of 5 to 25 km per hour.

Meanwhile, BMKG forecaster from the Class II Maritime Meteorological Station in Belawan, Medan, Christen Ordain Novena Marpaung, stated that from 21 to 24 June 2026, several waters in North Sumatra have the potential to be hit by high waves.

Wind patterns in the northern part of Indonesia generally move from Southeast to Southwest at speeds of 6 to 25 knots, while in the southern part, they generally move from Southeast to Southwest at speeds of 10 to 30 knots.

Waves of 1.25 to 2.5 metres are likely to occur in the East Waters of North Sumatra, West Waters of Nias Island, West Waters of North Sumatra, Waters of the Batu Islands, East Waters of Nias Island, and West Waters of the Batu Islands. Meanwhile, waves of 2.5 to 4 metres are likely to occur in the Indian Ocean west of the Nias Islands.