Mercury to hit 34 degrees as summer swelter begins, monsoon rains arrive this week

Temperatures soared on Sunday as Korea entered a stretch of full-fledged summer heat, with daytime highs reaching 34 degrees Celsius (93.2 degrees Fahrenheit).

A citizen blocks the sun using a parasol in Gwanghwamun, central Seoul, on June 8. [NEWS1]

Temperatures soared on Sunday as Korea entered a stretch of full-fledged summer heat, with daytime highs reaching 34 degrees Celsius (93.2 degrees Fahrenheit). Starting this week, southern regions, including Jeju, are also expected to see the beginning of the summer monsoon season.

According to the Korea Meteorological Administration (KMA), temperatures in Seoul rose to 30.4 degrees Celsius in the afternoon. Yangseong-myeon in Anseong and Okcheon-myeon in Yangpyeong, both in Gyeonggi, recorded the highest temperatures in the country at 34.3 degrees Celsius.

Morning temperatures have steadily risen in recent days as hot and humid air from the south has kept nighttime lows from dropping.

In Seoul, morning lows were around 15 degrees Celsius just days before the long weekend. But on Sunday, the morning low reached 21.4 degrees Celsius. On Friday, Memorial Day, Gangneung in Gangwon recorded a morning low of 24.5 degrees Celsius, nearly reaching tropical night conditions. In many regions, the daily temperature gap — which had been over 15 degrees Celsius — narrowed to less than 10 degrees Celsius, marking the start of the summer heat.

Children play at a fountain in Gwanghwamun, central Seoul, on June 5. [YONHAP]

The Haeundae Beach in Busan is filled with visitors on the afternoon of June 8. [JOONGANG ILBO]

The heat is expected to continue through Monday and Tuesday. Seoul’s daytime highs are forecast to hover around 30 degrees. While morning lows are expected to be around 19 degrees Celsius, high humidity will push the apparent temperature — the actual temperature felt by people in their everyday lives — to 22 degrees Celsius.

“The maximum apparent temperature will exceed 31 degrees Celsius in inland areas on June 9 and 10,” said a KMA official. “Avoid outdoor activities and outings due to the high risk of heat-related illnesses, and manage food carefully to prevent food poisoning.” Monsoon begins in China and Japan, Korea’s southern regions next

Monsoon rains are expected in southern parts of Korea — including Jeju — beginning midweek and continuing through the weekend. The seasonal rain front is gradually moving north and is expected to begin affecting the country.

Typically, the rainy season begins around June 19 in Jeju and June 23 in the southern mainland. This year, however, it is likely to arrive earlier than usual.

Citizens cool down with the cooling mist dispersed at a street in Busan on June 8. [JOONGANG ILBO]

In southern China, where the rainy season has already begun, heavy downpours have caused widespread flooding and damage. Japan’s Meteorological Agency has also warned that Kyushu will receive more than 200 millimeters (7.87 inches) of rain through June 10 due to the same stationary front.

A developing tropical disturbance in the Philippine Sea could further complicate conditions. If it strengthens into this year’s first typhoon — expected to be named "Wutip" — and tracks north toward the Korean Peninsula, it could push the seasonal rain front farther north and intensify rain clouds. This would expand the affected areas and increase the rainfall intensity.

However, the formation of the disturbance remains uncertain.

“Because the center of the low pressure is drifting inland, it is unlikely to create the kind of rotation needed to develop a tropical depression or typhoon,” said Kang Nam-young, a geography professor at Kyungpook National University. “Sea surface temperatures in the Philippine Sea are above 30 degrees Celsius, so a typhoon could still form at any time.”

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff. BY CHON KWON-PIL [yoon.soyeon@joongang.co.kr]