The strongest cold air so far this autumn swept northern China Thursday with most areas undergoing strong winds and a 4-8 degree drop in temperature.

Beijingers wear thick clothes to resist the cold gusts of winds on October 23, 2008. [Photo: Xinhua]

According to a China Central Television report, heating services in northeastern China's Heilongjiang Province and northwestern China's Xinjiang Uygur Autonomous Region have already started. Other provinces in the north have also started heating preparations.

Thursday also marks the first frost, one of the twenty-four solar terms on the Chinese lunar calendar, which means the weather will continue to get colder.