BEIJING, June 25 (Xinhua) -- China's national observatory on Saturday morning renewed its yellow alert for a heat wave in some southern and northern areas, where temperatures of between 35 and 39 degrees Celsius are predicted for the daytime.

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

During the daytime on Saturday, high temperatures of above 35 degrees Celsius are expected to scorch a vast region south of the Yangtze River and central parts of north China, the National Meteorological Center said.

Some parts of Guangdong, Jiangxi and Fujian provinces will see up to 39 degrees Celsius of high temperatures.

The center cautioned that local people should take precautions against high temperature.

The center also warned parts of Anhui, Zhejiang, Tibet, Qinghai, Hainan and Guizhou should brace for heavy rain from Saturday morning to Sunday morning.