Guo Liwen, head of the bureau's climate center said Beijing had an average temperature of 24.9 C in August over the past 30 years, relatively pleasant weather for the athletes.

He noted that there is no need to worry about the hot weather, adding that foreign media reports claiming that 29.8 C was the average August Beijing temperature were incorrect.

Guo said that 29.8 C is actually the average highest temperature in August.

The temperature and humidity in Beijing will decline gradually after August 7, the start of autumn in China's traditional lunar calendar, he added.

"Even if rare extreme weather hits Beijing in August, people will not feel muggy. High humidity will not accompany the hot weather in August because their climax periods are different," said Wang Yubin, the bureau's deputy chief engineer.

He explained that in August, the most humid hour of the day is in the morning, while the hottest hour is in the afternoon.

Relative humidity has been 77 percent in August over the past three decades, according to the bureau's research. The "heat index" of the Beijing Olympics is at the same level as Barcelona and better than that of Atlanta and Athens.

Wang said his bureau is capable of providing weather forecasts for Beijing and co-host cities six days in advance, as well as hour-by-hour forecasts for Olympic venues.

Beijing will also open an English-speaking weather hotline during the Games, he said.

Xinhua