A photo taken on Oct 9 shows a canon after snowfall in Jiayuguan, Northwest China's Gansu province. [Photo/IC]

By contrast, the vast southern and eastern regions, including Guangzhou, Guangdong province, saw sunshine and temperatures above 30 C on Monday. The heat will continue on Tuesday, Zhang said.

But the cold front sweeping the north will start to affect the southern region beginning on Wednesday. The front is forecast to bring heavy rainfall, she said.

For the southwestern region, heavy rain is forecast for the upper reaches of the Yangtze River and its tributary, the Hanjiang River, which will result in flooding around Thursday, according to the Yangtze River Flood Control and Drought Relief Headquarters on Monday.

In response, the headquarters ordered the Three Gorges Reservoir to prepare by cutting its outflow on Sunday and Monday to capture floodwaters.