The National Meteorological Center reported Monday there had been more than 25 days when temperatures exceeded 35 degrees Celsius (95 degrees Fahrenheit) in eight provinces and municipalities, Xinhua, the official government news agency, reported. That is the most since 1961.
The heat has been responsible for at least 40 deaths in the South.
The agency posted a second-level weather emergency Tuesday for the next 20 days. The designation is normally used for typhoons and floods.
The heat has been accompanied by drought in many areas. In Hunan province, more than 3 million people and 85 percent of the villages have been affected by the drought. The weather is also taking a toll on the bamboo forests.
On the plus side, a resident of Chongqing identified only as Lei told Xinhua the combination of hot weather and lack of rain has sharply reduced the mosquito population.