Beijing on Saturday maintained its hot weather alert at "red", the most severe in China's colour-coded warning system, with the Chinese capital expected to cross the 40 degrees Celsius (104F) threshold for a third straight day.
Nearby provinces including Hebei and Shandong also kept their "red" alerts on Saturday as vast tracts of northern and eastern China sizzled in record temperatures.
In China's four-tier weather warning system, the colour red indicates the most severe, followed by orange, yellow and blue. A red alert signifies the temperature could exceed 40C within 24 hours.
The latest heat waves, the second round in about 10 days, were caused by warm air masses associated with high pressure ridges in the atmosphere, the heating effect of which was amplified by thin cloud cover and long daylight hours around the summer solstice, according to Chinese meteorologists.
On Friday, Beijing baked in temperatures as high as 40.3C, after sizzling at 41.1C on Thursday, the second-hottest day recorded by the Chinese capital in modern times.
Until this week, the city of nearly 22 million people had never logged two consecutive days above 40C since setting up its main observatory in the southern suburbs in 1951.
Beijing's all-time high of 41.9C recorded on July 24, 1999, remains intact for now.
On Friday, education authorities in Beijing said schools would be allowed to reduce or even suspend classes if the weather becomes very hot.
The heat waves in northern China are expected to abate by Monday before regaining strengthen later in the week.
The southern and parts of central China, which have been kept cool by stormy weather, could see temperatures rise as high as 35C from June 27 as rains recede, meteorologists said.
China's weather bureau had previously warned of more hot days in most parts of the country this summer compared with previous years.
