Trying to keep rainfall away would have been very useful this summer. Centuries ago, possibly in the days of Elizabeth I, one way to attempt to stop the rain was using a rhyme: “Raine, raine, goe to Spain; faire weather come againe.” The saying was thought to be more powerful if recited while staring at a rainbow, which was probably a self-fulfilling move.

Rainbows often appear at the end of a shower when sunshine is beginning to break through.

However, Chinese meteorologists are taking more drastic action to keep rain at bay. The Chinese Weather Modification Office hopes to keep rain away from the opening ceremony of the Beijing Olympic Games in 2008 using anti-aircraft guns, rocket launchers and aircraft.

Usually this formidable arsenal is used for trying to get more rain to fall, rather than stay away. Silver iodide powder is shot or sprayed into clouds to mimic natural particles of salt or dust. These act as seeds for cloud droplets to form on. However, experts do not know how much rain would have fallen without any intervention.

To get rid of clouds, the Chinese plan to track any menacing clouds and trigger rainfall just before the Olympics open.