Inp.polri.go.id - Malang. The Meteorology, Climatology, and Geophysics Agency (BMKG) forecasts that the cold weather phenomenon locally known as "bediding" will persist across several regions until September 2025 due to prevailing dry-season winds.

Linda Firotul, a meteorologist at BMKG’s East Java Climatology Station, said on Sunday that the phenomenon is typical during Indonesia’s dry season and is driven by the dominance of dry and cold easterly winds.

“This phenomenon usually occurs from July to September and is marked by lower nighttime temperatures, especially in upland areas,” she said, as quoted by antaranews.com.

The cold air is intensified by clear skies at night, which enable faster heat loss from the Earth’s surface into the atmosphere.

While the dry season typically begins between April and June, lingering rainfall in some areas has delayed its onset due to atmospheric disturbances such as the Rossby waves, Kelvin waves, and Madden-Julian Oscillation (MJO).

In the Greater Malang region, average low temperatures range between 16°C and 20°C, with a 30-year historical average (1991–2020) at 17°C to 20°C. BMKG projects that August will mark the peak of the bediding, with minimum temperatures dropping to between 13°C and 15°C.

Bediding conditions can cause ground frost, or better known locally as “embun upas”, especially in highland areas such as Ranupane, a part of the Bromo Tengger Semeru National Park.

(mg/inp/pr/rs)