BEIJING -- China's national observatory on Wednesday renewed a red alert for high temperatures, the most severe warning in its four-tier weather warning system, as sweltering heatwaves hit many regions of the country.

During the daytime on Wednesday, parts of Shaanxi, Anhui, Hubei, Hunan, Jiangxi, Zhejiang, Shanghai, Fujian, Sichuan, Chongqing, Guizhou, Guangxi and Guangdong are expected to experience high temperatures of 35 to 39 degrees Celsius, according to the National Meteorological Center.

Temperatures in parts of Sichuan, Chongqing, Hunan, Jiangxi and Zhejiang may surpass 40 degrees Celsius, the meteorological center said.

It advised local authorities to take emergency measures against heatwaves, suspend outdoor work that is exposed to high temperatures, pay close attention to fire safety and take particular care of vulnerable groups.

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