Secrets of central heating

Beijing experienced its earliest snowfall since 1987 on Nov 1, prompting the municipal authorities to fire up the city's heating supply two weeks ahead of scheduled.

The supply usually runs from Nov 15 until March 15, and is regulated by the local government based on 20 years of research on weather and temperature trends by the Beijing Meteorological Bureau.

Like the capital, most cities in North China provide public heating services for all residents in winter.