South Korea expects high temperatures around 33 °C and heavy rainfall across Jeju Island and southern coastal regions this week [1].
These weather patterns signal the arrival of a summer monsoon-like system that could trigger flash flooding and disrupt travel in mountainous and coastal areas [2, 3].
Forecasters said the most severe precipitation will impact the southern coast and Jeju Island. Estimates for rainfall on Jeju Island range from more than 150 mm [1] to as much as 200 mm [5]. Similarly, projections for the southern coastal regions vary between over 80 mm [1] and up to 200 mm [5].
Seoul is also expected to experience the heat, with highs reaching 33 °C [1]. The timing of the heaviest downpours has seen slightly different projections among reporting sources, with some indicating the peak will occur Tuesday [2] and others citing Monday the 25th [5].
Residents in the southern regions are advised to monitor local weather alerts as the system moves inland. The combination of high humidity and intense rainfall often creates hazardous driving conditions, and increases the risk of landslides in the mountainous terrain of Jeju Island [1, 3].
Local authorities are preparing for the potential of widespread disruption. The forecast of up to 200 mm of rain in certain sectors represents a significant volume of water that can overwhelm urban drainage systems [5].
“Highs around 33 °C and heavy rain are expected over Jeju Island and southern coastal areas.”
The convergence of high temperatures and monsoon-level precipitation suggests a volatile start to the summer season. When rainfall reaches the 200 mm threshold in short windows, it typically exceeds the capacity of regional infrastructure, increasing the likelihood of agricultural damage and urban flooding in South Korea's southern provinces.
