Global warming is to blame for the recent temperature rises across China, an expert from the National Meteorological Center (NMC) said on Friday.
"Spring has come early in some areas of East and Central China this year, and it's because of global warming," Yang Guiming, the center's chief forecaster, told China Daily.
Temperatures in most cities rose above 20 C on Friday, 10 degrees above the seasonal average and despite some light rain falling the day before, the NMC said.
In large parts of Hunan, the mercury rose to 30 C, while Nanjing, capital of Jiangsu province, saw its highest temperature for the time of year in nearly a century, topping out at 27.7 C.
In Yibin, Sichuan, temperatures rose 10 C to 36 C in just an hour on Thursday afternoon, before falling back to normal later.
Fan Xiaohong, head of the provincial meteorological bureau, said the sudden rise was caused by a foehn wind, a type of arid wind that comes down from the mountains.
With the hot weather set to continue on Saturday, Yang warned authorities across the country to be alert to the danger of forest fires, such as have been witnessed in Hunan, Hubei, Guizhou, Fujian, Sichuan and Yunnan provinces since Wednesday.
On Thursday, a fire in Shaxian county, Fujian province, raged through two towns and eight villages, and brought local train services to a standstill.
More than 3,000 people, including firefighters, police officers and villagers, were mobilized to fight it, Lu Yueliang, the provincial deputy forestry chief, said.
Wind rekindled several forest fires hours after the blaze was brought under control on Friday morning. Flames were as high as 7 m as of 8 pm.
But no casualties have been reported, the official said.
Two people were killed, however, and two others were injured in two forest fires in Guizhou province on Thursday.
Some 651 forest fires broke out last month, damaging 2,005 hectares, the State Forestry Administration said.
Yang said the risk of fires should lessen from Sunday, when temperatures are expected to fall.
Provinces including Shandong, Henan, Anhui, Hubei and Jiangsu will see 1-4 mm of rain over the weekend, the NMC forecast.
The average temperature in those provinces is expected to drop below 10 C.
A rare snowstorm hit Liaoning province on Friday, forcing 17 expressways to close.
The snow was the heaviest for this time of the year in 25 years, according to Han Jiangwen, chief weatherman of the Shenyang observatory.