Tropical storm Pabuk, which hit Hong Kong on Friday, brought rain to south-eastern coastal provinces, offering temporary relief to the lingering drought there.
But it also caused floods across the southern province of Guangdong, toppling houses and affecting about 1.2 million people.
Downpours and rainstorms were recorded in Wenzhou and Taizhou in the eastern province of Zhejiang, which have suffered more than 20 days of sweltering heat.
Heavy rains also brought relief to 65,500 people and 30,300 hectares of scorched farmland in Fujian in the south-east.
A drizzly Hong Kong itself was getting back to normal on Monday after a severe storm warning forced markets, schools and ferries public facilities to close early on Friday.
More than 1,100 people were evacuated to avoid possible landslides after heavy rains hit Dandong, a city in the north-east province of Liaoning.
Mines in two counties under the jurisdiction of Dandong city were ordered to suspend operations as rain was expected all week.
Three more tropical storms are expected to form in coming days, threatening China and neighbouring Taiwan.
The tropical storms, as opposed to full-fledged typhoons, come at the tail-end of a summer over which a series of natural disasters in China has killed nearly 1,000 people in floods, landslides and house collapses.