China's meteorological authority renewed an orange alert Saturday evening as a heat wave is expected to sweep across many areas of the country.

On Sunday, much of central and southern China will be in the grip of the heat wave with temperatures in parts of Shanghai as well as Henan, Shandong and Fujian provinces hitting 37-39 degrees Celsius, according to the National Meteorological Center (NMC).

Some areas are even likely to see temperatures surpass 40 degrees Celsius, it added.

The NMC advised people in affected regions to take precautions against heat stroke and fire, including avoiding outdoor activities.

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