BEIJING, Dec 11 (Reuters) - The first snowfall of winter arrived in Beijing early Monday, covering the Chinese capital with a mantle of white overnight and plunging the city into freezing temperatures, with even colder weather looming this week in northern China.

Snowfall reached 5.8mm (0.23 inch) on average by early Monday, with the highest snowfall of 10.2mm recorded in Fangshan district, Beijing Meteorological Service data showed.

Beijing typically sees its first snow of the season between late November and February, or even none at all. More snowfall is expected this week, with temperatures seen further sliding to as low as minus 20°Celsius (minus 4°F).

The Chinese capital last saw such similarly frigid weather on Jan. 7, 2021, when the mercury dropped to minus 19.6°C.

The cold snap in Beijing this week, compared with the autumn-like conditions a week ago, mirrored the sharp swings in temperatures recently. In October, Beijing experienced one of its warmest Octobers in decades in a year of weather extremes.

Beijing's all-time low of minus 27.4°C, set on Feb. 22, 1966, remains unbroken.

On Monday, Beijing's weather bureau warned of road icing in large parts of the city of nearly 22 million, with authorities shutting some expressways or partially closing sections.

By 10 a.m. local time (0200 GMT), 62 out of a few hundred flights had been cancelled at the Beijing Capital Airport.

Railway authorities enforced speed limits on lines connecting Beijing and Guangzhou in southern China, causing delays in some passenger trains.

By 7 a.m. Monday, more than 180 bus routes in Beijing had been suspended.

The official Beijing Daily reported that vegetable stocks were ample, hitting this year's highest daily market volume of 23,800 tonnes, as merchants stocked up ahead of time.

Huang, a Beijing resident working in the internet sector, said the snow in Beijing came early.

"Normally, it doesn't snow until the Spring Festival," Huang said, referring to the start of the Lunar New Year, which typically falls in January or February.

In northern Shanxi province, a highway pile-up on Sunday involving 40 vehicles due to icy road conditions injured six and left one dead.

In central Henan province, schools were suspended for the day in the provincial capital of Zhengzhou, which had recorded 14.2mm of precipitation with a snow depth of 10cm.

In Jinan, capital of eastern Shandong province, schools moved their classes online. (Reporting by Liz Lee, Ryan Woo and Xiaoyu Yin. Editing by Gerry Doyle)