BEIJING - China's national observatory on Sunday renewed its orange alert for a cold wave amid the coldest weather in decades.

According to the National Meteorological Center (NMC), temperatures dropped 10 to 13 degrees Celsius on Sunday morning in parts of Northwest China, North China and the area between the Yellow River and Huaihe River.

In the middle and lower reaches of the Yangtze River, the lowest temperatures could reach minus 12 degrees Celsius from Sunday to Monday, said the NMC.

Temperatures in parts of Zhejiang, Fujian and Guangdong are forecast to approach or even drop below the lowest levels on record, it said.

Temperatures in central and eastern China were 6 to 8 degrees Celsius lower than the average historical level.

China has a four-tier warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.