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Seoul sets record with highest number of July tropical nights, August tipped to be hotter

Published: 01 Aug. 2025, 11:35 Updated: 01 Aug. 2025, 12:06

KIM JU-YEON
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People seek relief from the heat at Cheonggye Stream in central Seoul on July 31. [YONHAP]

Korea entered August locked in an unrelenting heat wave, with overnight temperatures in Seoul and Incheon staying above 25 degrees Celsius (77 degrees Fahrenheit) on Thursday — a condition known as a tropical night.

The Korea Meteorological Administration (KMA) forecast daytime highs between 30 and 37 degrees Celsius for Friday, with Jeongeup and Gyeongsan expected to peak at 37 degrees. Seoul, Daejeon and Daegu are also bracing for 36-degree highs. Gwangju is forecast to hit 35 degrees, while Incheon will reach 34 degrees and both Ulsan and Busan will hit 32 degrees.

Meteorological authorities register tropical nights based on the starting date of the night, meaning Thursday's overnight heat capped off a record-breaking July.

According to the KMA, Seoul recorded its hottest July since data collection began in 1908. The city’s average temperature for the month hit 28.6 degrees Celsius, breaking the 1994 record of 28.5 degrees. As of 5 p.m. Thursday, the city’s low was 29.3 degrees, with a high of 34.6 degrees — enough to seal the new monthly record.

A worker cools off at a construction site for the Yangjae-daero project in Gangnam District, southern Seoul, on July 31. [YONHAP]

Seoul also saw the highest number of tropical nights ever recorded in July. Counting Friday night, the temperature stayed above 25 degrees Celsius on 23 of the month’s 30 days — over 70 percent — exceeding the previous record of 21 days set in 1994.

Between Wednesday and Thursday night, the mercury never dipped below 29.3 degrees Celsius, marking the hottest July night on record.

Children cool off in mist from a cooling fog system at the National Debt Redemption Movement Memorial Park in Jung District, Daegu, on July 31. [YONHAP]

The record-breaking heat was largely due to a prolonged heat wave that followed the end of the monsoon season. Temperatures in the greater Seoul area hovered near 40 degrees Celsius for days.

The nationwide heat also appears to be eclipsing previous record summers, such as those in 1994 and 2018. From June to July 30, the national average daily high reached 30.1 degrees Celsius, surpassing 29.9 degrees Celsius in 1994 and 29.5 degrees Celsius in 2018. The daily average temperature and nighttime lows also hit record highs of 25 degrees and 21 degrees Celsius, respectively.

An official from the Daegu Meteorological Administration points to a real-time monitoring device showing a temperature of 38.6 degrees Celsius (101.5 degrees Fahrenheit) near Banwoldang intersection in Jung District, Daegu, on July 31. [YONHAP]

The heat is expected to persist in the coming days. Some experts warn that August will likely be hotter than July.

“Sea surface temperatures across the Northwest Pacific, including areas around Korea, remain abnormally high,” said Kim Baek-min, an atmospheric science professor at Pukyong National University.

“That will likely expand and reinforce the North Pacific high, making August another extremely hot month.”

The KMA also projected that August’s average temperature would be "generally higher than normal.”

“August is typically hotter than July and marks the core period of the summer heat,” said Woo Jin-kyu, a senior KMA analyst. “We cannot rule out the possibility of extreme heat surpassing 40 degrees [Celsius] nationwide.”

BY CHON KWON-PIL, KIM JU-YEON [[email protected]]