Beijing began monitoring weather in the Tian'anmen Square area round the clock on Saturday in preparation for China's 60th National Day, in an echo of procedures during the 2008 Beijing Olympic Games, said an official with the Beijing Municipal Meteorological Bureau Sunday.

The weather forecast for a one-kilometer area around the square will be broadcast every day from now on until the National Day celebrations are completed, said Guo Hu, head of the Beijing Municipal Meteorological Observatory.

The climate then however would be "different from the monitoring of summer Olympic weather. The National Day is in early autumn when visibility in Beijing is low but celebrations especially military parade really requires high visibility," Guo said.

"This will be a new challenge for us to cover more weather details, such as the visibility, low clouds and cloud cover, in our broadcasting," Guo said.

Beijing has set up a network, including seven fixed and two mobile monitoring observation stations, according to the China Meteorological Administration. Four satellites will report the weather every 15 minutes and radar in Beijing reports every six minutes.

The Beijing Weather Modification Office said it was prepared to interfere in the weather during the National Day if it rains.

Weather records show that the probability of rain in Beijing during the National Day is 30 percent but the rain was usually only light, the observatory said.

But bad weather including heavy rain and fog, storms, and even hail had occurred on National Day previously. Heavy rain had fallen in 1959, 1976, 1979, 1996 and 1999, according to records.

(Xinhua News Agency August 31, 2009)