South Korea monsoon begins with heavy rain in Jeju and heat in Seoul

South Korea's nationwide monsoon season began on July 1, bringing heavy rainfall to the south and extreme heat to the capital region.

The arrival of the jangma season marks a critical period for the peninsula's agriculture and infrastructure, as the timing and intensity of rainfall can lead to significant flooding or drought.

Jeju Island experienced an intense start to the season, recording more than 200 mm ^[1] of rain. While the southern coast and central regions also saw activity, the weather patterns remained inconsistent across the country.

In Seoul and the surrounding metropolitan area, the monsoon front did not fully arrive. Instead, the region endured hot and humid conditions with only brief, intermittent showers. The morning temperature in Seoul reached 22 °C ^[2].

According to the Korea Meteorological Administration, a low-pressure system attached to a stationary front moved north faster than expected. This movement expanded the cloud band into the central region, officially starting the monsoon for that area.

"As the low pressure accompanying the stationary front developed, the rain cloud belt expanded to the central region, and accordingly, the monsoon season began in the central region," said Kong Sang-min, a forecast analyst for the Korea Meteorological Administration ^[1].

Despite the official start, the stationary front has since retreated toward the southern seas. This shift has caused the heavy rains to subside in some areas, leading to a surge in temperatures. Officials said daytime temperatures nationwide are expected to rise above 30 °C ^[2].

This year's onset is the third latest on record ^[1]. It also marks only the seventh time a July monsoon has begun in central Korea ^[1].