Korea has seen “unusual” weather, such as heat wave, record rainfall and early frost, in September.
The first frost of the season was spotted on Mt. Seorak in the country's east on Friday, 11 days earlier than last year and amid a series of abnormal weather conditions this month, according to local forecasts.
Temperatures in the eastern province of Gangwon, where Mt. Seorak stands, fell to as low as 3.1 degrees Celsius in some areas and hovered below 10 degrees in other regions early Friday morning, the Gangwon Regional Meteorological Administration said. Marking the coldest weather this fall, the temperature fell 2 to 4 degrees from Thursday.
The temperature drop comes after heavy rains pounded the capital area earlier this week, leaving two people dead and forcing nearly 12,000 people out of their homes.
Seoul was pummeled with 259.5 millimeters of rain on Tuesday, as much as 289 mm in some parts, marking the heaviest downpour in the city for September since recordkeeping began in 1908, according to the Korea Meteorological Administration (KMA). It was the second highest September record for the capital since it was hit with 268.2 mm of rain on Sept. 1, 1984.
Tuesday's downpour was also the second heaviest rainfall per hour, reaching 75 mm at its peak, compared with 116 mm on Sept. 13, 1964.
"We couldn't imagine so much rain late in September," said a KMA official. "The heavy downpour will have to be seen as another case of exceptional weather."
The weather has been out of the normal range throughout the year, from the cool spring to the scorching hot, rainy summer across the country.
The average temperature in April was around 9.9 degrees -- the lowest ever for the month, according to records available from 1973. Summer temperatures, meanwhile, rose above the yearly average by 1.3 degrees to reach 24.8 degrees, while August rains were the most frequent in Seoul since 1908, with 24 days of rainfall.
The heat wave continued through mid-September, with the average temperature nationwide reaching 28.4 degrees from Sept. 1-22, or 2 degrees above the average in previous years. Seoul's daytime temperature topped 30 degrees during nine of those 22 days.
"Last year, daytime temperatures in Seoul never rose above 30 degrees throughout the month of September," a KMA official said. "This year, high pressure from the North Pacific persisted over a long period and caused the temperature to rise across the country."