Lee Hae-rin is a City Desk reporter at The Korea Times, covering social issues, tourism and taekwondo. She is passionate about speaking up for the rights of minorities, including women, LGBTQ+, people with disabilities and animals as well as discovering the latest makgeolli trend in town. Feel free to reach her at lhr@koreatimes.co.kr.
Warming climate extends Korea’s mosquito season beyond summer
gettyimagesbank
By Lee Hae-rin
For generations, Koreans took comfort in an old saying: “After Cheoseo, mosquitoes lose their bite.” The seasonal marker, which fell on Aug. 23 this year, traditionally signaled the shift to cooler autumn weather.
But that wisdom no longer holds.
Recent studies show that in Korea, mosquito activity now reaches its peak not in midsummer but well into autumn, as climate change reshapes the insect’s life cycle in unexpected ways.
Data from the Seoul Research Institute of Health and Environment showed that more mosquitoes were observed in the fall than in the summer last year.
Between April and November, 16,997 mosquitoes were collected in light traps across the capital. More than half — 54.3 percent, or 9,234 — were observed in the fall months of September through November. October alone accounted for 5,087, more than twice July’s total of 2,511.
The shift has been consistent in recent years. Between 2015 and 2019, mosquito activity typically peaked in July or August. Since 2020, however, the peak has moved to September, October or even November, with 2022 seeing the latest surge in the first week of November.
Mosquito repellent products are displayed at a large supermarket in Seoul, Monday. Yonhap
Experts say rising summer temperatures are altering mosquito behavior.
Mosquitoes, cold-blooded insects that thrive at around 26 to 27 degrees Celsius, have had their metabolism accelerated and lifespan shortened by extreme heat.
When temperatures exceed 33 degrees, their survival time can shrink to just a week. “At very high temperatures, mosquitoes conserve energy and refrain from flying,” said Lee Dong-kyu, professor of environmental health at Kosin University.
Moreover, heavy rains and flash floods, which have grown more frequent with climate change in recent years, damage mosquito habitats in the summer by washing away larvae. As a result, mosquitoes now find the cooler, more stable conditions of autumn better for reproduction and blood-feeding.
“Mosquitoes nowadays tend not to appear much in the summer but increase as the weather cools,” an official from the Seoul Research Institute of Health and Environment said. “There is a possibility that, like last year, many mosquitoes will be caught in the fall this year as well.”