South Korea officially entered the monsoon season on June 30, 2026, bringing heavy rain to the south and extreme heat to the capital.
This meteorological divide highlights the volatile nature of the region's seasonal transitions, where extreme precipitation and heat waves can occur simultaneously in different provinces.
Jeju Island experienced the most severe impact of the season's start, with rainfall exceeding 200 mm [1]. The heavy downpours affected the island and southern coastal areas as a low-pressure system associated with a stationary front moved northward.
In contrast, the Seoul metropolitan area remained dry. A weather reporter said a heat wave warning was issued for the city, where the actual daytime temperature reached 33 °C [2]. The perceived temperature in the capital was even higher at 34 °C [2].
Korea Meteorological Administration forecaster Gong Sang-min said the rain clouds expanded toward the central region as the low-pressure system developed, marking the start of the monsoon for those areas. However, the stationary front had not yet reached the capital region, which kept the area hot and dry.
Forecasters expected isolated showers ranging from five to 40 mm in inland areas later that day [3].
Data indicates that this year's monsoon start is the third latest on record since observations began [4]. For the central region, this marks only the seventh July monsoon on record [5].
“Jeju Island recorded rainfall exceeding 200 mm as the monsoon season began.”
The delayed arrival of the monsoon, the third latest on record, combined with the stark contrast between Jeju's flooding and Seoul's heat, suggests a highly unstable atmospheric pattern. This disparity in weather extremes can strain national disaster response resources, as the government must simultaneously manage flood mitigation in the south and heat-related public health risks in the urban north.
