Heavy rain showers are expected to hit southern South Korea and Jeju Island starting tonight [1, 2].

These weather patterns signal the arrival of early-summer moisture, which can lead to localized flooding and disrupt travel across the southern provinces. The intensity of these showers varies by region, with some areas facing more severe conditions than others.

Forecasters expect rainfall between 10 and 40 mm in Jeolla-do and Gyeongsangnam-do tonight [1]. Jeju Island is facing more significant precipitation, with totals reaching up to 80 mm by early tomorrow morning [1].

While the south experiences these showers, other parts of the country may see high temperatures. Daytime highs across the nation could reach up to 32 °C on June 13 [3]. Additional torrential downpours are expected to hit southern Korea and Jeju Island on Tuesday [2].

Beyond these immediate showers, weather services are monitoring a more severe phenomenon. A nationwide "water-bomb" rain event is forecast for June 20 [4]. This specific weather event is characterized by extreme intensity, with heavy rain expected to fall at a rate of approximately 30 mm per hour [4].

These conditions are driven by seasonal early-summer weather patterns [5]. Moisture-laden air masses are moving into the region, creating the volatile conditions necessary for both sudden showers and the projected "water-bomb" events [5].

“Rainfall up to 80 mm expected on Jeju Island”

The transition into the early-summer monsoon season in South Korea often brings unpredictable and intense precipitation. The forecast of a "water-bomb" event, defined by high-volume rainfall in a short window, suggests a risk of flash flooding and infrastructure strain, particularly in the southern provinces and Jeju Island where the initial rains are concentrating.