In the east and northwest of China, temperatures as high as 43.9 degrees Celsius have scorched Zhejiang, Jiangsu, Shanghai, Anhui and Xinjiang in recent days, state broadcaster CCTV said.
The observatory of Zhejiang's provincial capital Hangzhou recorded a 41.9 degrees Celsius historical high on Saturday (Aug. 3). The city of 12.5 million people is expected to swelter under temperatures exceeding 40 degrees Celsius through Aug. 11.
Chinese meteorologists say the record heat this year has been aggravated by high continental temperatures owing to global warming, even as the La Nina weather phenomenon brings cooler-than-average sea surface temperatures in the equatorial Pacific.
Earlier this year, China was hit by its warmest spring since 1961 when it started to compile modern-day data. That was followed by the country's hottest May, triggering weeks of drought-like conditions in central China in June, hitting crops and livelihoods of farming communities in the region.
With the extreme heat this summer, electricity usage has also risen due to increased demand for air-conditioning. The spike in electricity demand could threaten a supply crunch.
Zhejiang's State Grid since last month began recommending electric vehicle owners charge their vehicles late at night to stagger electricity use from daily peak hours.
It also advised people to turn off air-conditioning when temperatures were milder.
The national weather forecaster on Monday cautioned of potential fire hazards caused by excessive power consumption and excessive electrical loads.
In the coming days, many areas around the Yangtze River delta can expect sizzling weather of above 37 degrees Celsius after daily maximum temperatures at seven national weather stations breached local historical extremes.
Jiangsu's observatory issued a red warning for heat on Sunday after high temperatures which had persisted for more than a week further intensified. The mercury could reach 40 degrees Celsius in cities of Wuxi, Changzhou and Zhenjiang, CCTV said.
Hangzhou is expected to see 10 straight days of above 40 degrees Celsius weather, breaking its record of eight days in 2013.