An interesting question for the future is concerns the "right" of countries to make it rain. The moisture that is being prematurely forced into rain could have become rain for South Korea, Japan, Taiwan, etc. A whole slew of problems from water access to denying rain for political purposes to others are just some potential things which may lie in the future.The technology to seed rainclouds works thusly - silver-iodide pellets are shot in the air, around which moisture coalesces to help clouds form earlier than they otherwise would, creating rain. China is also working on "busting" clouds, to create clear skies for the Olympics, as well as other science-fictiony stuff.
This brings up the idea of Wx and climate intelligence again. While Kent's Imperative would condescendingly insinuate that, due to my young age, I'm brainwashed [a mindset imprinted by the media-generated cognitive biases (the results of decades of politically correct environmentalism targeted at the younger generation in the schools)], and/or desire to change the definition of intelligence to create new jobs because I can't compete for existing ones [the desire to find new accounts not yet dominated by the gray beards and talking heads of the community], I still stubbornly think climate intel is important. The issue of weather control highlights three facets of weather/climate intelligence.
1) Those practicing weather control obviously need good intelligence on droughts, floods, etc., so that they know where to encourage rainfall and where to discourage it.
2) If someone upwind of you is seeding clouds to "steal your rain," what do you do about it? Like Catholicgauze implied, Korea, Japan, etc. should have intelligence on how China is controlling their weather due to the impact it will have on their own weather patterns. The inverse would also apply - if Laos and Vietnam are both flooded and Laos busts clouds so they dump their rain over Vietnam instead of Laos, that could create additional death and destruction in Vietnam.
3) Countries (or non-state actors) could use weather control systems to practice economic warfare. Without climate intelligence to tell you whether current weather patterns are normal or not, a victim country might never know whether they had bad luck with the weather, or were being actively sabotaged.
One final possibility is some form of weather trading system, like carbon credits. i.e., if Japan's economy doesn't depend on agriculture to the extent that China's does, then Japan could sell some "rights" to China to seed clouds that would otherwise rain over Japan. Then weather intelligence would be necessary to maintain adherence to the trading protocols.