South Korea Records Hottest Day Ever as Mercury Hits 42.5°C in Yangsan

South Korea recorded its highest temperature since national weather records began more than a century ago, with the mercury touching 42.5 degrees Celsius in the southeastern city of Yangsan on Sunday, the state weather agency said.

The Korea Meteorological Administration (KMA) said the reading was logged at 1:26 pm local time (0426 GMT). Yangsan has been the focal point of an intense heatwave that has seen temperatures exceed 40°C for a fifth consecutive day.

Much of the country remains under heat warnings, with several cities experiencing daytime highs in the high 30s Celsius. More than 20 localities were placed under emergency heatwave alerts on Sunday, a new warning category introduced this year to better respond to rising temperatures. An emergency alert is issued when an area is forecast to experience perceived temperatures of 38°C, or an actual temperature of 39°C, for at least one day.

KMA data show that the average annual number of heatwave days in South Korea has more than doubled over the past five years compared with the 1970s — from eight days to 19. A heatwave day is defined as a day with a maximum temperature of at least 33°C, while a tropical night is when the overnight low remains at or above 25°C.

The record-breaking heat has raised concerns about public health, energy demand, and agricultural output. Prolonged exposure to extreme heat can cause heat exhaustion and heatstroke, particularly among vulnerable populations such as the elderly and outdoor workers. Officials have urged residents to stay hydrated and avoid outdoor activities during peak afternoon hours.

Scientists have repeatedly warned that human-induced climate change is making extreme weather events such as heatwaves more frequent and intense. Global average temperatures have risen by more than 1 degree Celsius since pre-industrial times, and Asia has experienced some of the most pronounced warming trends. South Korea's summer temperatures have been climbing steadily, with recent years seeing more frequent and prolonged hot spells.

The KMA expects the current heatwave to persist for several more days, with little relief expected overnight. Night-time temperatures in many areas have remained above 25°C, adding to the discomfort and health risks. The government has activated emergency response measures, including cooling centres in public facilities and increased monitoring of vulnerable groups.

While the exact contribution of climate change to individual weather events requires detailed attribution studies, the overall pattern is consistent with scientific projections. Experts say that limiting global warming to 1.5°C, as outlined in the Paris Agreement, would reduce the frequency and severity of heatwaves, but current emissions trajectories suggest otherwise.