Weather manipulation is actually not as rare as one might think. Currently, 24 countries practice some kind of cloud seeding. Moscow's mayor keeps the Russian Air Force on cloud seeding duty to make sure it never rains on his parades (literally). The U.S. has dabbled with weather manipulation in attempts to curb the intensity of Gulf hurricanes back in the '60s, and the military seeded clouds over North Vietnam during the war there to extend the monsoon season. Oh, and the CIA seeded clouds in 1969 in an attempt to rain out the hippies gathering at Woodstock, but they partied right through it anyhow (that instance is unconfirmed, but groovy to think about).

more about China's manipulation on weather click here