South Korea's record-breaking heat wave is expected to marginally ease this weekend after reaching its peak on Friday, 8 August, according to the Korea Meteorological Administration (KMA). The slight relief will come as a shift in the pressure system over the Korean Peninsula weakens the dual grip of the North Pacific High and the Tibetan High — the two systems driving the current extreme conditions.

What the Forecast Shows

On Friday, morning lows across the country are expected to range from 22°C to 27°C, while daytime highs will stretch from 31°C to 39°C. Seoul is forecast to record a low of 27°C and a high of 39°C.

By Saturday, daytime highs are projected to ease to a range of 27°C to 36°C — still well above the 30-year average (1991–2020) for the same date, which sits between 29°C and 33°C for afternoon peaks. The KMA has also forecast heavy rain along the east coast and on the southern island of Jeju over the weekend, as weakening high-pressure systems allow clouds into the upper atmosphere and reduce solar radiation.

Despite the weekend dip, relief will be short-lived. Sultry conditions are expected to return from Monday, with daytime highs ranging between 28°C and 36°C through the following week, as the North Pacific High reasserts its influence. Perceived daytime highs could reach around 35°C, the KMA said.

The Human Cost So Far

The toll from the heat wave has been severe. Health authorities confirmed on Wednesday that 21 people have died from heat-related illnesses in South Korea so far this year — surpassing last year's full-season total of 20 deaths. Notably, this year's fatality count is higher despite fewer overall patients compared to the same period last year.

According to the Korea Disease Control and Prevention Agency, a total of 2,441 patients visited emergency rooms for heat-related conditions between mid-May and Tuesday, when the heat-illness surveillance system has been active. Among reported cases, heat exhaustion accounted for the largest share at 61.7%, followed by heat stroke at 16.8% and heat cramps at 11.5%.

One of the most recent fatalities was a 60-year-old man who collapsed while working outdoors on a farm in Eumseong county, North Chungcheong Province, on Tuesday.

Why This Heat Wave Is Unusually Intense

The KMA attributed the extreme conditions to the simultaneous presence of the North Pacific High and the Tibetan High over the peninsula — a relatively rare convergence that traps heat and suppresses cloud formation. This dual-high configuration is expected to hold only through Friday, after which the connection between the two systems will weaken.

This comes amid a broader pattern of intensifying summer heat across East Asia, with climate scientists increasingly linking such extreme events to long-term warming trends. South Korea has recorded multiple heat-wave emergencies in recent years, though the current season's mortality rate — higher than last year despite fewer hospitalised patients — points to a more vulnerable population being affected.

What Authorities Are Advising

Health officials have urged residents, particularly outdoor workers and the elderly, to limit exposure during peak afternoon hours, stay hydrated, and seek shade or air-conditioned spaces. The spike in farm-related fatalities underscores the risk to agricultural workers who have limited ability to pause work during heat emergencies.

With above-normal temperatures forecast to persist well into next week, authorities are expected to keep the heat-illness surveillance system on high alert through at least mid-August.