Monsoon season over, but dog days of summer just starting: KMA

The state weather agency said last Saturday marked the end of the monthlong monsoon season, with sweltering heat and tropical nights gripping the nation for now.

A child reads a book lying on a wooden bench in the shade at Busan Citizens Park in Busanjin District, Busan, on Tuesday. [YONHAP]

The state weather agency said last Saturday marked the end of the monthlong monsoon season, with sweltering heat and tropical nights gripping the nation for now.

“As of Saturday, nationwide monsoons have practically come to an end,” said the Korea Meteorological Administration (KMA) in a briefing on Tuesday, adding that the nation will be affected by a subtropical high for some time.

This year’s monsoon season began on June 19 for Jeju Island, June 22 for southern regions and June 29 for central regions. The nation has since experienced frequent heavy rains, resulting in deaths and injuries, property damage and floods.

Children cool off at a water playground in Gyeongmyeong Park in Seo District, Incheon, on Tuesday. [YONHAP]

The announcement follows the dissipation of volatile atmospheric conditions caused by a recent typhoon.

Earlier, the KMA said that the continuation of monsoon rains depended largely on Typhoon Gaemi — which formed from a tropical depression east of the Philippines on July 20. The potential impact of the typhoon on the peninsula’s rain clouds prevented the KMA from predicting the monsoon's end, the agency said.

However, the typhoon weakened and a subtropical anticyclone took its place, pushing the stationary front — responsible for the torrential rains — northward to North Korea. This development led the KMA to conclude that the monsoon season had ended.

Typhoon Gaemi struck northeastern Taiwan with gusts of up to 227 kilometers per hour (141 miles per hour) early on July 25 and made a second landfall in southeast China’s coastal Fujian province on Thursday before weakening.

This year, the monsoon season lasted seven days longer than the average of 32.4 days on Jeju Island and four days longer than the 31.4-day average in southern regions. However, central regions, where the average duration is 31.5 days, experienced a monsoon season that was three days shorter than usual.

The average total precipitation nationwide for this year’s monsoon period until July 27 was 472 millimeters (18.6 inches), 1.3 times higher than the 356.7 millimeters average from 1991 to 2020. This places this year’s monsoon season in the top 16.6 percent of the past 30 years.

However, the KMA said the exact beginning and end dates of this year’s monsoon season will be confirmed in mid-September after a thorough post-analysis of observational data.

With the monsoon season’s end, scorching heat is expected to take over the nation.

As of Tuesday, heat wave alerts had been issued across most of the country, including Jeju Island, which has been under a heat advisory since July 17.

Currently, high atmospheric pressure from Tibet and the North Pacific overlap near the nation, causing temperatures to soar.

Many areas are expected to endure prolonged tropical nights, with daytime temperatures in Gyeongsang and the East Sea expected to exceed 35 degrees Celsius (95 degrees Fahrenheit).

The KMA, however, reminded us that the onset of the heat wave does not signify the end of rainfall. The potential for torrential rain persists due to the substantial amount of residual water vapor in the atmosphere.

No significant rain is forecasted this week, although brief showers are expected in the greater Seoul area and western Gangwon on Friday due to low pressure moving southward.

BY WOO JI-WON [woo.jiwon@joongang.co.kr]