UPDATE 1-Olympics-Beijing rockets rain away from opening gala

(Recasts with rain dispersal rockets)

By Lindsay Beck

BEIJING, Aug 9 (Reuters) - Thundershowers were forecast for hazy Beijing on Saturday, after the Olympic hosts fended off wet weather for the Games' eye-popping opening ceremony by firing a volley of rain dispersal rockets into the skies.

It was the largest such operation undertaken in China, the official Xinhua news agency said, and the first time such technology had been used to ward off showers over an Olympics opening.

The host nation has been experimenting with "cloud seeding" to induce rain over the city as well as scrupulously tallying its "blue sky" days in an effort to curb stubborn pollution.

But overcast, still weather thwart its attempts to showcase clear skies to the world as the Games begin.

Pollution has been a persistent problem for Games organisers, with millions of dollars poured into a clean air plan that has taken over half the city's 3.3 million cars off the road and closed dozens of factories around Beijing.

But the city has still struggled to control pollutants that could pose a major problem for endurance events.

Officials have a back-up plan to take more cars off the road in Beijing and nearby cities and close more factories, but they are holding off in the hope the weather will clear by itself. On Saturday, a high of 33 degrees Celsius (91 Fahrenheit) was expected, but a heavy downpour could clear some of the haze. More rain was also forecast for Sunday.

Hong Kong, host to the Olympics equestrian events which began on Saturday, had bright skies with light mist early, with the temperature at 25 degrees Celsius (77 F).

Relative humidity was at 91 percent, but that was drier than the heavy rainfall of the last few days, during which a severe tropical storm hit.

The city is expected to have sunny intervals, possible isolated showers and a maximum temperature of around 30 degrees Celsius (86F) on Saturday, the Hong Kong Observatory said. The air pollution level was rated "low". (Additional reporting by Sophie Taylor; Editing by Nick Macfie) (For more Olympic stories visit our multimedia website "Road to Beijing" here; and see our blog at blogs.reuters.com/china)