Considering the size of the country, its climate is extremely diverse, ranging from tropical regions in the south to the sub-arctic in the north. Hainan Island is located at roughly the identical latitude as Jamaica, at the same time Harbin, which is one of the largest cities in the north, is located at about the same latitude as Montreal, and its climate matches Montreal. Northern China has four different seasons with very hot summers and bitterly cold winters. South China tends to be milder and wetter. The farther you travel north and west, it tends to have a drier climate. When you leave East China and step onto the majestic Tibetan highlands or into the extensive steppes and deserts of Gansu and Xinjiang, the differences in distance are vast and the land is very harsh.
In the days of the planned economy, the rules stipulated that buildings in areas north of the Yangtze River received heat in winter but not in the south – this meant unheated buildings in places like Shanghai and Nanjing, where temperatures routinely drop below freezing in winter. The rule has long been relaxed, but the effects are still visible. Typically, Chinese people use less heat and less building isolation and also wear more warmer clothing compared to Westerners in similar climatic conditions. In schools, apartments and office buildings, the corridors are not heated, even if the rooms are heated. Double glazing is quite rare. During classes, both students and teachers usually wear winter jackets, in addition long underwear is common. Air conditioning is becoming more common, but is also not used in corridors and is often used with open windows and doors.