Bediding Phenomenon Also Affects Semarang at Night

Residents of Semarang and its surrounding areas have felt a fairly extreme difference in air temperature between day and night in recent days. The condition has forced the public to adapt because of concerns it could affect health.

Observations in a number of highland and lowland areas on Wednesday (10/6) showed clear to cloudy weather. Daytime air temperatures reached a range of 18 to 34 degrees Celsius, making it feel hot and stuffy. However, at night, temperatures dropped drastically to below 14 degrees Celsius, creating a fairly piercing cold.

“The change in temperature between day and night is very pronounced, so the body becomes feverish,” said Dewi (48), a resident of Sumowono, Semarang Regency. A similar complaint was voiced by Nur Aini (65), a resident of Semarang City. She admitted to having to wear a jacket and use a thick blanket at night because the air temperature felt much colder than during the day.

Responding to these conditions, the Head of the Central Java BMKG Climatology Station, Goeroeh Tjiptanto, explained that the significant temperature change is a natural process that occurs at the beginning of the dry season. According to him, during the day the earth’s surface absorbs heat from sunlight, while at night that heat is released back into the atmosphere and outer space. The process of heat release becomes more maximal when the sky is clear without cloud cover.

“Because the clear sky has nothing to block it, there are no clouds that act as a natural blanket to help retain some of the heat in the atmosphere,” said Goeroeh. He explained that the reduced number of clouds at night means the heat stored on the earth’s surface is more easily released, causing the air temperature to drop faster. This condition is a common characteristic during the dry season, when rainfall decreases and the night sky tends to be clearer.

Even though the public refers to this condition as the ‘bediding’ phenomenon, Goeroeh stressed that the cold air felt cannot necessarily be categorised as such because it does not occur consistently every day and is very dependent on atmospheric conditions. “This phenomenon is a natural process that commonly occurs during the dry season. BMKG urges the public to maintain their body’s health condition because the temperature difference between day and night can be quite significant,” he said.

BMKG reminded the public to maintain their immune systems, wear clothing appropriate to the weather conditions, and meet their fluid intake needs to stay healthy amidst the fairly extreme temperature changes during the dry season.