Office worker Bae Ji-won couldn’t get a cab one snowy night after a late night drinking session last week.

After 20 minutes of trying past 2 a.m., she decided to spend the rest of the night at a nearby jjimjilbang, a dry sauna where people bathe and often sleep.

On her way, she stopped by a 24-hour convenience store to pick up some emergency commodities.

She first bought a can of warm honey water and a pair of socks as her boots and socks were soaked with snow.

She also bought thermal underwear, planning to stave off the piercing cold the next morning when she goes to work.

“I was wearing sheepskin boots with thick fleece on the inside and a long down jacket, but I was shivering after standing in the cold and my feet were freezing and wet,” she said.

As the mercury has dropped below -10 degrees Celsius more often than usual this winter with surprisingly heavy snow every week, retailers saw sales of certain products rise sharply.

“It’s not just snow chains for car tires that sell well when it snows,” said Song Wan-seop, spokesman for GS Retail which runs GS25 convenience stores and GS iSuper, an online version of GS Supermarket.

“Sales of underwear for both men and women as well as socks jumped on snowy days as many people gave up going home in the snow and spent the night elsewhere.”

On Dec. 5, for example, when heavy snow fell across the Seoul metropolitan area and Gangwon Province, sales of underwear for women and men at GS25 stores in cram school zones jumped 321.5 percent and 232.6 percent, respectively, from a week earlier.

Sales of socks also soared 46.3 percent on Dec. 5 as people dropped by convenience stores to change into a dry pair.

In GS25 stores surrounded by office buildings, sales of underwear and socks for women climbed 71.1 percent and 30 percent, respectively, on the same day.

In the first 10 days of December, GS25 saw hot pack sales nearly triple compared to a year ago.

Sales of typical winter snacks such as chocolate bars, steamed buns and warm soybean milk rose nearly 20 percent.

More people dropped by convenience stores to buy extension cords last month compared to a year ago due to a surge in the use of electric heating appliances, Song said.

Sales at GS iSuper also rose 39 percent on-year in the extremely chilly three days from Jan. 2, as people chose to buy groceries online instead of going out in the cold.

At E-mart, the nation’s largest supermarket chain, sales of paper weather strips used on windows for weatherproofing from Dec. 1 through Monday jumped 75.6 percent from a year ago.

Sales of hot packs, electric heaters, electric mats and sleighs also have increased significantly at E-mart so far this winter.

Different items are in great demand at department stores depending on the mercury level.

“Mufflers are popular when the temperature is between zero and -5 degrees Celsius, whereas gloves sell like hot cakes when it goes below -10 degrees,” a sales clerk at Lotte Department Store said.

Last month was colder compared to the average December temperature in the past of between zero and -1 degrees, driving up sales of goose down coats and jackets as well as thermal undergarments.

Goose down sales increase sharply when the mercury hits below -5 degrees.

“Goose down clothing sales rose up to 15 percent on the day when the temperature first fell to -6 degrees last December,” said a spokesman for Bean Pole Outdoor brand at Cheil Industries Inc.

Sales of winter undergarments start to rise when the mercury drops below zero and strikingly shoots up when it nears -15 degrees.

Vivian, a major lingerie maker, said its sales of undergarments on Jan. 1 and 2 jumped 178 percent compared to a year ago.

According to research by Shinhan Investment Corp. on the sales trend and temperature changes during the winter season since 2003, clothing sales at department stores inched up 1.2 percent, when the monthly average temperature between October and February dropped by a degree.

By Kim So-hyun (sophie@heraldcorp.com)