Dieng's Embun Upas (Toxic Dew) has become a tourist attraction, with tourist visit numbers showing an increase.

The upas dew phenomenon has once again appeared across the Dieng Highland Tourist Area, Banjarnegara, Central Java during the 2026 dry season. This thin coating of ice crystals that blankets grass and vegetation does not only create a striking unique landscape, but has also become a major visitor drawcard.

Many families intentionally travel to the area before dawn to witness upas dew, which only forms when air temperatures drop below freezing point.

Tursiman, Head of the Banjarnegara Regency Tourism and Culture Office (Dinparbud), confirmed that upas dew is a regular natural occurrence in the Dieng Highlands, most commonly observed around the Arjuna Temple Complex during every dry season.

"This is an authentic natural phenomenon that occurs here seasonally. We want the public to be aware of it, and we welcome tourists to visit and experience this special atmosphere," he stated.

According to Tursiman, pre-dawn temperatures in Dieng regularly fall below zero degrees Celsius between July and August. Historical records show temperatures typically range between minus 1°C and minus 2°C, and can drop even colder under specific weather conditions.

Due to its rare distinctive nature, upas dew functions as a reliable seasonal tourist attraction. Local authorities continue to promote this phenomenon to boost visitor numbers, while simultaneously running campaigns to remind the public to protect the natural ecology of the Dieng tourist reserve.

The positive impact of this weather event is already measurable, with clear increases in tourist arrivals recorded during the school holiday period.

Eko Sri Wurjani Juniasih, Head of Institutional, Human Resources and Marketing Division at Banjarnegara Dinparbud, confirmed that visitor enthusiasm has risen very significantly.

"Thankfully this occurrence lines up perfectly with the school holidays. We have seen a very sharp spike in arrivals directly linked to reports of upas dew. This unusual natural phenomenon has captured huge public interest, bringing crowds of visitors to Dieng, most travelling here with their families," she explained.

Upas dew has been recorded between six and seven times so far this dry season. The first occurrence was observed in early June when temperatures hit minus 2°C, with further events recorded repeatedly through early July.

On the morning of Thursday 9 July, official readings from the Dieng Regional Technical Implementation Unit registered temperatures dropping as low as minus 6°C, marking one of the coldest minimum temperatures recorded this dry season.

Ticket sales data confirms a consistent upward visitor trend throughout 2026. Arrivals were recorded at 69,225 in January, 32,982 in February, 87,031 in March, 68,799 in April, 89,793 in May, before surging to 131,970 visitors in June. For the first 9 days of July 2026 alone, visitor numbers have already reached 67,421.

Dinparbud has stated hopes that the cold conditions which produce upas dew will persist through until the 2026 Dieng Culture Festival (DCF), scheduled for 28–30 August. The presence of this frosted landscape during the festival is expected to provide an additional major attraction for domestic and international tourists.

Upas dew forms when overnight and pre-dawn air temperatures drop low enough that atmospheric water vapour freezes directly onto exposed surfaces, depositing a fine layer of ice crystals over grass and vegetation. This snow-like white landscape covering the Dieng plateau is also referred to locally as ice dew.