The seventh round of heavy rain to hit Hubei Province, between June 7 and 10, affected a total of 105,000 people and 17,500 hectares of farmland and caused economic losses of 41.7 million yuan ($5.96 million).

With more heavy rain expected in most of south China, local meteorological centers in Chongqing, Guizhou, Hubei, Hunan, Anhui, Jiangxi and Guangxi had been asked to have staff work shifts around the clock.

Early rains

"Many people feel the heavy rains have been abnormal. Actually, China as a whole has entered the flood season when a lot of rain falls. The precipitation of this year so far is normal compared with the same period of a regular year," said Yang Guiming, Chief Weather Broadcaster at the National Meteorological Center (NMC), during an interview with Oriental Morning Post on June 10.

Yang explained that the rainy season began slightly later this year than in a regular year in Guangdong and Guangxi and earlier in provinces along the Yangtze River, and this simultaneousness occurrence made people feel that the rain was unusual.

Most of China has a continental monsoon climate with more drastic seasonal temperature variations compared with other regions at the same latitude, such as North America and Western Europe, according to experts. From September to April the following year, winter monsoons blow from Siberia and the Mongolian Plateau, resulting in cold and dry winters and wide variations in the temperatures of north and south China. From April to September, warm and humid summer monsoons blow from the seas in the east and south, resulting in overall high temperatures and plentiful rainfall, as well as little variation in temperature between north and south.

The rainy season of the middle and lower reaches of the Yangtze River, also called "plum rain season" with plum ripening in the region, is caused by rain belts that form when moist air over the Pacific meets the cooler continental air mass. "Usually the rainy season in this region lasts for over 20 days since the middle of June," Sun Jun, Chief Weather Broadcaster of NMC, told Beijing Review.

Meteorological authorities in Anhui and Zhejiang announced that the two provinces had entered the rainy season on June 8, eight days earlier than the usual inception date. Sun told Beijing Review, in the first 10 days of June, four provinces along the Yangtze River recorded up to twice the rain of the same period of an average year while in Guangdong and Guangxi, some areas had three times the rain of a normal year.

However, Wang Yongguang, a researcher with the National Climate Center, told Beijing Review it was too early to predict a particularly heavy "plum rain season." He said the latest La Nina, the extensive cooling of the central and eastern Pacific, since mid-2007, is yet to exert influence on China's rainy season. He said La Nina would mean more-than-usual precipitation in China's more arid north and a short and weak "plum rain season" during the monsoon season.

Wang said the trend of China's climate change since the giant El Nino of 1997-98 has included waning rainy seasons in the middle and lower reaches of the Yangtze River, colder winters and more frequent extreme weather events since 1999.