SEOUL: South Korea registered its highest temperature since records began more than a century ago on Sunday (Aug 2), as authorities warned people to “immediately” stop all outdoor activities in affected areas.

The southeastern city of Yangsan saw the temperature reach 42.5°C at 1.26pm local time (12.26pm, Singapore time), the Korea Meteorological Administration said on its website.

Yangsan has been the epicentre of the ongoing heatwave, where temperatures exceeded 40°C for a fifth consecutive day on Sunday, while many other cities including Daegu and Busan are seeing temperatures climb into the high 30s.

People flocked to air-conditioned shopping malls or cafes to escape the blistering temperatures, an AFP reporter saw.

Ju Dong-yeol, 27, took refuge from the heat in a Starbucks in Seoul along with his parents and told AFP “it is too hot to be outside doing anything”.

“I can’t think of anything else to do other than stay in air-conditioned places like home, shopping malls and cafes,” the office worker said.

More than 20 localities were under emergency heatwave alerts on Sunday – a new warning category introduced this year to better address rising temperatures.

An emergency alert is issued when areas experiencing a heatwave are forecast to hit perceived temperatures of 38°C or an actual temperature of 39°C for the day.

Issuing a heat warning, the weather agency urged people to “immediately stop all outdoor activities”, adding that “indoor spaces without air conditioning are dangerous”.

“Move immediately to a cool place, such as a designated cooling centre or a shaded area, and stay hydrated while resting,” it advised.  

KMA data show the average annual number of heatwave days in the country has more than doubled to 19 over the past five years, from eight in the 1970s.

A heatwave day is defined as one with a maximum temperature of at least 33°C.