The monsoon season began on Jeju Island this week, bringing heavy rainfall and prompting official warnings for strong winds and flooding [1].

This weather event is significant because the arrival of the monsoon was notably delayed this year, which can alter agricultural cycles and increase the risk of flash flooding when rains finally arrive.

Rainfall began on Tuesday, according to reports from YTN [1]. The heaviest precipitation was recorded on Hallasan, where rainfall reached a maximum of 230 mm [1]. Other areas were also heavily impacted, with the eastern coastal region of Pyeongseon recording more than 110 mm [1].

Weather authorities said that the intensity of the storm was driven by the specific topography of Hallasan and the influence of strong south-west winds. These factors contributed to hourly rainfall rates of 30 mm in the mountain ranges, as well as the southern and eastern regions [1].

"Currently, the monsoon rain continues in Jeju," said reporter Ko Jae-hyung, who reported from the vicinity of Jeju Airport [1].

The timing of this season's onset differs sharply from previous years. The monsoon began 12 days later than the average start date [1]. When compared specifically to last year, the start of the season was delayed by 19 days [1].

Local authorities have issued heavy-rain and strong-wind warnings to residents and travelers. The combination of high-volume rainfall and wind gusts has created hazardous conditions across the island's varied terrain [1].

“Hallasan recorded a maximum of 230 mm of rainfall.”

The significant delay in the monsoon's arrival, nearly three weeks later than the previous year, suggests a shift in regional weather patterns. When a delayed season begins with high-intensity bursts, such as the 30 mm per hour rates seen in Jeju's highlands, the saturated ground and sudden volume increase the likelihood of landslides and urban flooding.