South Korea recorded its highest temperature since modern meteorological records began in 1904 on Sunday, when the southeastern city of Yangsan reached 42.5 degrees Celsius at 1.26 pm local time, according to the Korea Meteorological Administration. The city has been at the epicentre of a heatwave that has kept temperatures above 40°C for five consecutive days, the agency said.

The heatwave has caused at least 13 heat-related deaths and 1,781 heat-related incidents between 15 and 31 July, according to government data cited by The Independent. Prime minister Han Seong-sook confirmed that the government activated level two of its disaster response headquarters, urging the public to avoid outdoor activities during midday. The weather agency warned that indoor spaces without air conditioning are dangerous and called on residents to move to cool places immediately.

Sources disagree on when South Korea introduced a new emergency heatwave warning category: some reports state it was introduced this year, while others say it was introduced last year. The alert, issued for more than 20 regions on Sunday, is triggered when the heat index reaches 38°C or the actual temperature reaches 39°C for at least one day.

Data from the Korea Meteorological Administration shows that the average annual number of heatwave days – defined as days with a maximum temperature of at least 33°C – has more than doubled from eight in the 1970s to 19 over the past five years. Scientists have warned that extreme weather events such as heatwaves are becoming more frequent and intense due to climate change caused by human activities. The government response remains at level two, and the heatwave is expected to persist through the coming week.