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Korea faces hottest summer ever after record-setting June temperatures

Published: 06 Jul. 2025, 15:37

Tourists line up in front of a ″Squid Game″ experience zone under their parasols in Gwanghwamun, central Seoul, on July 4. [NEWS1]

Korea is on track to face the most extreme summer heat in its history, with no signs of relief in sight after enduring the hottest June on record. Some forecasts warn that temperatures may surpass 40 degrees Celsius (104 degrees Fahrenheit).

According to the Korea Meteorological Administration’s (KMA) climate report for June released on Friday, the national average temperature last month was 22.9 degrees Celsius, the highest since records began in 1973. This breaks last year’s record of 22.7 degrees Celsius after just one year.

The average maximum temperature for June, 28.2 degrees Celsius, was the second-highest on record, following last year’s 28.4 degrees Celsius. Both the number of days under heat wave advisories and the number of tropical nights also ranked second-highest in recorded history. On June 19, 12 regions — including Daejeon, Daegu and Gwangju — saw their earliest-ever tropical night. In Seoul, tropical nights in June have now occurred for four consecutive years since 2022.

The weather agency explained that a high-pressure system southeast of the Korean Peninsula intensified, bringing in southwesterly winds that kept temperatures above seasonal norms.

“Between June 27 and 30 in particular, hot and humid air moved in and strong sunlight during the day led to heat waves and tropical nights,” the agency said.

Tourists walk around the Gyeongbok Palace in central Seoul on July 2. One tourist, center, has taken off the long-sleeved jeogori top due to the heat. [NEWS1]

A citizen cools himself down in front of a cooling fog set up in central Seoul on July 1, when a heatwave advisory was issued across the country. [YONHAP]

The rainy season had been hoped to bring some kind of relief — but it failed to deliver. Rain began earlier than usual, on June 12 in Jeju Island and June 19 to 20 in central and southern regions — three to seven days earlier than average. But after an initial downpour, the rain weakened into a dry spell. In fact, the rainy season ended early in Jeju on June 26 and in southern regions on July 1.

The North Pacific high-pressure system has since taken hold, bringing clear skies and intensifying the heat. Heat wave warnings are in effect across most of the country, with sweltering temperatures during the day and tropical nights at night.

A heat wave warning is issued when the maximum perceived temperature exceeds 33 degrees Celsius for more than two days, or when significant damage is expected due to the heat. A tropical night is defined when temperatures stay above 25 degrees Celsius between 6:01 p.m. and 9 a.m. the following day.

This weekend, temperatures in southern regions are forecast to soar to 37 degrees Celsius. In Seoul, high humidity will push the heat index to as much as 34 degrees Celsius. While parts of the capital region and Gangwon Province may see light showers of around five millimeters (0.2 inches) on Sunday, the amount will be far too small to bring any meaningful relief. According to the KMA, no significant rainfall is expected until the latter half of next week.

Tourists at the Haeundae Beach in Busan on July 6 [SONG BONG-GEUN]

Citizens cool themselves down at the Gwanghwamun Square in central Seoul on July 1. [YONHAP]

Meteorologists warn that the shortened rainy season could lead to a longer and more intense heat wave than last year. With the heat arriving about a month earlier than usual, there is concern that the scorching conditions will persist. In the summer of 2018 — which went down as the worst on record — an early end to the rainy season was followed by an extreme heat wave. That year, Seoul reached 39.6 degrees Celsius, with nationwide heat wave advisories issued for 31 days — still the longest period on record.

“Because the rainy season ended even earlier than in 2018, this year’s heat wave could last longer,” said Son Suk-woo, a professor of earth and environmental sciences at Seoul National University. “We can’t rule out the possibility of temperatures surpassing 40 degrees Celsius.”

Korea Meteorological Administration Administrator Chang Dong-eon also urged the public to prepare thoroughly, saying, “With heat waves and tropical nights continuing across the country since the end of June, people must take precautions to avoid heat-related harm.

Early heat and tropical nights have already driven a sharp increase in heat-related illnesses. According to the Korea Disease Control and Prevention Agency, 633 people visited emergency rooms for heat-related conditions such as heatstroke between June 15 and the end of the month — a rise of more than 30 percent compared to the same period last year. Five of those patients died. On July 2 alone — when heat wave alerts were in place across most of the country — 100 people were reported to have suffered heat-related illnesses. Among the total patients, 30.6 percent were aged 65 or older, and the highest number of cases, 12.3 percent, occurred between 4 p.m. and 5 p.m.

Translated from JoongAng Sunday using generative AI and edited by Korea JoongAng Daily staff.
BY CHON KWON-PIL [[email protected]]