BANGKOK – Bangkok is set to become the hottest major city in South-east Asia by 2050, with temperatures projected to rise above 38 deg C as climate change and the urban heat island effect intensify across the region.

The warning comes from the report “Roadmap for Extreme Heat Protection through Passive Cooling in ASEAN Region” by the ASEAN Centre for Energy, which says Thailand’s capital faces a far more severe heat crisis in the decades ahead.

In 2025, Bangkok has around 45 “extreme heat days” a year, defined as days when temperatures exceed 35 deg C. By 2050, that number is expected to rise to 120 days a year, meaning residents could face almost three times more days of accumulated extreme heat within just a few decades.

The report also projects that Bangkok’s average daily maximum temperature will climb to 38.1 deg C by mid-century, up nearly 5 deg C from 33.3 deg C in 2000.

Compared with other major ASEAN cities, Bangkok is forecast to record the highest temperature in 2050, followed by Ho Chi Minh City in Vietnam at 37.7 deg C, Manila in the Philippines at 37.2 deg C, Kuala Lumpur in Malaysia at 36.9 deg C, Jakarta in Indonesia and Singapore at 36.1 deg C.

Such conditions could push the city’s infrastructure, public health system and economy towards unprecedented limits.

The report identifies climate change and rapid urbanisation as the two main forces driving ASEAN’s worsening heat crisis. In Bangkok, the urban heat island effect is a major factor, as concrete and asphalt absorb heat during the day and release it at night.

Data from the Asian Disaster Preparedness Centre (ADPC) shows that dense central areas of Bangkok can be up to 3 deg C hotter than greener outer areas. Rising heat directly threatens public health by increasing the risk of heatstroke, chronic fatigue and sleep problems that damage quality of life.

Economically, severe heat could hit labour productivity, especially among more than 1.3 million outdoor workers in Bangkok. The report says that without proper adaptation, econ...