Over the weekend alone, fierce storms and hail killed 17 people across four provinces.
Ten died in the central province of Hubei, where rain and hail have added to swollen waters along the country's longest river, the Yangtze, and its main tributary, the Han.
In the northwestern province of Shaanxi, five died in floods that cut off roads around Shangluo, Xinhua news agency said.
A hail storm on Saturday hit parts of the eastern province Anhui, where millions of residents have been grappling with the threat of the swollen Huai River for the past month, killing one person and injuring three, Xinhua said.
Flood waters on the Huai have begun to retreat, but 268,000 people, including 8,000 troops, remained stationed along its embankments to prevent any breaches, it added.
One person died in a lightning strike in weekend storms in the flood-battered southwestern province of Sichuan, Xinhua said.
Summer storms are nothing new in China, but experts said global warming driven by growing greenhouse gas emissions from factories, farms and vehicles was fuelling more intense weather.
"The frequency and intensity of extreme weather events are increasing -- records for worst-in-a-century rainstorms, droughts and heatwaves are being broken more often,"Dong Wenjie, director-general of the Beijing Climate Centre, said in an interview on its Web site (www.ncc.cma.gov.cn).
"This in fact is closely associated with global warming."
Global warming is usually associated with drought, but warmer, moister air is likely to bring more concentrated storms to many parts, scientists say.
Overall, rain may not become more abundant, chief forecaster of the China Metereological Administration, Wang Yongguang, told the China Daily.
"Heavy rainfall doesn't increase the total precipitation level because it is distributed unevenly over time and space," he told the paper.
Floods have affected 119 million people, or nearly one tenth of China's 1.3 billion population, and caused economic losses of 52.5 billion yuan ($7 billion), Xinhua said.
Farmers have borne the brunt of the damage and casualties, underscoring the vulnerability of the huge rural population to natural disasters.
But coal miners in central China have also become victims of the storms. Sixty-nine miners in Henan have been trapped since Sunday in a pit flooded by rainwater that surged through an old shaft, Xinhua reported.
Rescuers have pumped out water and drilled holes to provide oxygen to the trapped miners.
Forecasters said torrential rain was likely to hit parts of the southwestern provinces Guizhou, Yunnan and Sichuan as well as Hubei in the coming days. Storms could also soak the country's dry north on Monday.
Other parts of China are suffering meteorological misery of different kinds.
More than 1 million people faced shortages of drinking water in several southern provinces as a heatwave compounded weeks of drought.
China coal mine flood traps 69
Sixty-nine miners were trapped in a flooded Chinese coal pit operating above its design capacity, state media reported on Monday.
Rescuers had pumped out water and drilled holes to provide oxygen to the miners who were swamped after a flash flood caused by heavy rain raced through an old shaft about 200 km (125 miles) west of Zhengzhou, the capital of central Henan province.
The miners have been trapped since Sunday morning. Thirty-three people had managed to escape the state-owned mine, operated by Zhijian Mining Co. Ltd., Xinhua news agency said.
"The rescue operation is going on in an orderly way and the most important task is to try every effort to pump water for the time being," it said, quoting a rescue official.
Xu Guangchun, Henan's provincial Communist Party boss who rushed to the scene with Li Yizhong, head of China's top work safety watchdog, was able to talk to some trapped workers by telephone on Sunday night, Xinhua said.
It was still raining on Monday morning, hampering rescue efforts, Xinhua said.
China's coal industry is the world's deadliest, killing an average of 13 people a day last year. Most of the deaths occur in small private unregulated mines, but large state-run collieries report much higher death tolls when accidents hit.
The Zhijian mine, which was founded in 1958 during the Great Leap Forward, had a designed annual production capacity of 210,000 tonnes, but actually produced 300,000 tonnes each year, Xinhua said.