Clad in a fox fur hat and dog hair boots, Mongolian merchant Undrakhiin Batulzii says his compatriots have over centuries mastered the art of beating the brutal winters of the steppes.

Ulan Bator is regarded as the world's coldest national capital and can see bone-chilling winter lows of minus 40 degrees Celsius, tough even for the hardy descendants of Genghis Khan.

For a newcomer the temperatures can be achingly uncomfortable, especially if stationary. Exposed ears and hands quickly begin to hurt, while standing on frigid concrete overcomes extremities not shod in properly insulated footwear.

"Staying warm is worth 1,000 lan of gold," goes one Mongolian saying, placing a monetary value on avoiding the cold -- with one lan weighing 37 grams, it is the equivalent of $1.4 million.

But Mongolians cope by means of fancy fur hats, hot food and drink, stoic good humour and layers of clothing -- "There are no fashionable people in winter," goes another saying.

"Mongolians' ancestors were nomads," said Batulzii at his traditional garment stall in Ulan Bator's outdoor Naran Tuul market.

"Everything we eat and wear is designed to overcome the difficulties of the four seasons," he added. "That's why Mongolians can beat the winter with no trouble."

Ulan Bator lies at a surprisingly benign latitude south of Paris, but is 1,300 kilometres (800 miles) inland, far from the moderating influence of the oceans, and at an altitude of 1,350 metres (4,430 feet).

Known as the land of the "Eternal Blue Sky", high pressures from Siberia give Mongolia cloudless winter nights that allow daytime land warming to escape to the atmosphere, and send temperatures plunging.

According to World Meteorological Organization 30-year figures, Ulan Bator's average annual temperature is -2.4 degrees C (28 F), well below the 2.7 C of Kazakhstan's Astana, Reykjavik in Iceland at 4.4 C and Moscow, which enjoys a comparatively balmy 5.0 C.

Byambaagiin Yanjmaa, a retired kindergarten cook, credits traditional food and drink as key for getting through the coldest months.

"Horse and lamb are very good for surviving the winter. Sheep find the best grass from the pastureland," she said in one of Ulan Bator's "ger" districts, largely poor, hard-scrabble areas where many homes are collapsible, felt-covered herders' dwellings.

"It's not so bad," said the 69-year-old. "Everyone can adapt to it based on his or her strength and weakness."

Nearby, workers broke up jet black raw coal into pieces to sell as heating fuel, a key contributor to the city's dire pollution levels.

In Tov province west of the capital, herder Tumursukhiin Altanzaya tends her horses, cows, sheep and goats, including milking the bovines, all out in the cold, but said her lambskin deel -- a long Mongolian tunic -- and wool boots help keep her warm.

"I ride a horse, and herd animals," she said. "When I get back home from the pasture, I drink aarts and eat khuushuur" -- a hot sour curd beverage and meat dumplings.

- 'Surprisingly warm' -

Mongolia is periodically hit by deadly winters known as zud, marked by heavy snow and cold so severe that livestock are unable to graze, lose strength and freeze to death on the open steppe, sometimes destroying herder livelihoods. Millions of livestock died in the last one in 2010.

About 1.3 million people live in Ulan Bator -- more than 40 percent of Mongolia's population.

The lowest temperature recorded in the city so far this year was -34 Celsius on January 26, according to weather information service Weather Underground, but residents said the winter has been relatively mild.

"This year it's surprisingly warm," said Begziin Dalai, a spry 86-year-old retired driver and father of eight, warming a bare hand over a meat-hawker's open fire on a sunny but sub-zero afternoon.

Clyde Goulden, curator emeritus of the Academy of Natural Sciences of Drexel University in the United States, who researches Mongolia's climate, lists the country's plateau location and large open expanses as among factors that make it cold.

Still, Mongolia's average temperature has warmed more than two degrees Celsius, or almost four degrees Fahrenheit, over the past 40-50 years, he said, citing studies.

The average world increase is about one degree Celsius, he told AFP, but the trend for Arctic and nearby regions is higher.

"It's just highly variable," he said. "More and more now the herders say the weather is changing so quickly that they can no longer predict what the next winter will be like."

Damdinii Norjmaa, 84, lives in a small ger in Ulan Bator but still pines for the pastures where she once herded cattle.

"I think winter is good," she said. "Because winter makes us much stronger."