(ATTN: UPDATES with Jeju airport's extended closure, school schedule change, airliners' measure)
SEOUL, Jan. 24 (Yonhap) -- South Korea on Sunday experienced the coldest weather this winter with temperatures dropping to record lows.
The temperature in Seoul fell to minus 18 degrees Celsius, the lowest since Jan. 15, 2001, when the mercury dropped to minus 18.6 degrees, the Korea Meteorological Administration (KMA) said.
It said the cold wave will continue through Monday before a let-up around noon the next day.
Amid the weekend's freezing weather, nearly 600 flights, mostly to and from the resort island of Jeju hit by heavy snow, were canceled and more than 700 vessels were stranded, according to the Ministry of Public Safety and Security.
People largely stayed indoors, with traffic significantly reduced in Seoul.
A school in Suwon, just south of Seoul, and three others in Jeju delayed an end to a month-long winter break until Tuesday.
On Saturday, the state weather agency issued a cold wave warning for Seoul for the first time in five years. Such a warning is issued if the morning low drops at least 15 degrees from the previous day and at least 3 degrees compared with the average year, or if the temperature remains below minus 15 degrees for two or more days.
Other parts of the country, including Gyeonggi Province and Incheon, near Seoul, were also subject to the warnings.
The KMA urged special precautions for health and facilities, saying strong winds could cause the temperature to feel colder.
The weather notably reduced the number of people on the streets and cars on the roads.
"The number of people visiting Myeongdong was cut to 10 percent compared to last week," a street vendor in the bustling area in downtown Seoul said. "Today, there are less people here than yesterday."
At Seoul's Yongsan station, a train's departure was delayed by 9 minutes because a door froze in the few minutes that it was left open, according to the train's operator.
On the southern resort island of Jeju, tens of thousands of travelers have been stranded since Saturday with runways closed due to heavy snow and cold weather.
The Jeju International Airport, the island's only airport, has decided to close its runways until 8 p.m. Monday. More than 510 flights to and from Jeju have been canceled Sunday, stranding as many as 60,000 people.
Many roamed inside the airport as airport and local administration officials scrambled to help them find transportation back to the city and accommodations there.
Hotels near the airport were packed with travelers forced to stay on the island. People also struggled to get taxis from the airport.
Some travelers voiced frustration about certain airlines, saying they were not informed of the flight cancellations.
However, Korean Air, Asiana Airlines and other carriers said they have no plans to reimburse the passengers as the disruptions were due to natural causes.
Instead, they have decided to operate dozens of extra flights from Jeju as soon as the airport reopens.
Meanwhile, in North Korea's northeastern tip, the mercury dropped to minus 37.5 degrees on Saturday night, according to the South Korean weather agency.
Temperatures in Pyongyang dropped further from minus 15 degrees on Saturday to minus 19 degrees early Sunday.
North Korean authorities have also issued cold wave warnings and urged people to take special care not to get frostbite, according to North Korean state media.
U.S.-based Radio Free Asia reported Saturday that more than 40,000 North Korean workers have been withdrawn from construction sites amid the freezing weather.
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