BMKG Refutes Reports of Surabaya Temperatures Reaching 48 Degrees Celsius

Air temperatures in the city of Surabaya, East Java, were reported to have reached 48 degrees Celsius according to the Wet Bulb Globe Temperature website on Sunday (4/9). However, the Agency for Meteorology, Climatology, and Geophysics (BMKG) has refuted these claims.

BMKG Juanda forecaster Oky Sukma Hakim stated that, according to their monitoring, the maximum air temperature in Surabaya stands at 37 degrees Celsius. However, there is potential for temperatures to rise throughout October 2026.

“For this October period, which is still within the dry season, the maximum air temperature is predicted to increase up to approximately 37 degrees Celsius,” Oky said when confirmed on Monday (5/10).

The report of 48 degrees Celsius in Surabaya was previously disclosed by the Race Director of the Surabaya Isoplus Marathon 2026, Safrita Aryana. He mentioned that the marathon event had to be halted on Sunday (4/10) because Surabaya’s air temperature showed readings of 42, 46, and even briefly 48 degrees Celsius.

Responding to this, Oky stated that the information regarding Surabaya’s temperature reaching 48 degrees Celsius was not the result of BMKG observations. He suggested that the figure could originate from non-BMKG data or might refer to the heat index felt by human skin.

“The issue of temperatures exceeding 40 degrees Celsius likely stems from non-BMKG data, or the temperature intended is the heat index felt by human skin, rather than the actual air temperature,” he said.

Furthermore, Oky noted that default weather applications on smartphones usually display the ‘feels like’ temperature. This figure is calculated using several variables, including air temperature, humidity, and wind speed.

“Because the observed air temperature and the heat index felt by human skin can differ—where higher humidity with the same air temperature makes the heat feel more intense to our skin—it can lead to such discrepancies,” he explained.

Oky advised the public to avoid direct exposure to sunlight during the day as it can impact skin health. “Use protective clothing or sunscreen, and consume water according to the body’s needs to avoid dehydration,” he urged.