Dieng Plateau Freezes Over, Temperatures Drop to Minus 1 Degree Celsius
The Arjuna Temple area in Dieng Kulon Village, Dieng Plateau, Banjarnegara Regency, Central Java, has frozen and become covered in frost. The phenomenon of frost, or ‘bun upas’, has blanketed the Dieng area in recent days alongside the arrival of the dry season, causing temperatures there to touch minus 1 degree Celsius.
The Secretary of Dieng Kulon Village, Sabar Alfarisi, stated that the appearance of frost has been visible for the past few days as air temperatures continue to decrease from night to morning. “For approximately the last three days, frost has begun to appear in Dieng. It is visible around the Arjuna Temple area and several other open areas,” he said on Tuesday (9/6/2026) afternoon.
According to him, this natural phenomenon, which is a hallmark of the dry season in Dieng, always attracts the attention of tourists. Consequently, many visitors arrive in the early hours of the morning to witness and capture the formation of thin ice crystal layers on the surface of grass and plants.
“Many tourists have arrived to see and photograph the frost. This phenomenon is indeed always a unique attraction for visitors to Diint,” he said.
The Head of the Meteorology, Climatology, and Geophysics Agency (BMKG) Central Java Climatology Station, Goeroeh Tjiptanto, said the emergence of ‘bun upas’ this year was triggered by dry weather conditions in recent days. Based on BMKG data, rainfall in the Dieng area during the period of 6-9 June 2026 was recorded at 0 millimetres.
“Zero millimetres of rainfall indicates that the atmosphere is in a very dry condition. Additionally, the sky tends to be clear without clouds from night to morning,” he said.
He explained that the lack of cloud cover allows the heat stored on the earth’s surface during the day to be released maximally into the atmosphere and space at night. According to him, this condition causes the cooling process to occur rapidly, resulting in a drastic drop in ground surface temperatures.
“Based on data, the minimum air temperature in Dieng on 9 June 2026 reached 1.05 degrees Celsius at 01:01 WIB. Meanwhile, the temperature of the grass or ground surface was recorded even lower, at 0.60 degrees Celsius at 08:30 WIB,” he said.
He added that these conditions allow for the formation of thin ice crystal layers on grass, agricultural plants, and other surfaces directly exposed to the cold air. He noted that the topography of Dieng, which consists of a basin surrounded by mountains, further strengthens the formation of frost.
“Cold air from the mountain slopes moves downwards at night and becomes trapped in the valley floor, causing the temperature in the area to be much lower than in surrounding regions,” he said.
In relation to this, Goeroeh urged the public and tourists visiting Dieng to prepare warm clothing and to be wary of extreme cold temperatures, which are expected to potentially continue for the next few days, especially from night to morning.