I think the massive fires would affect weather far more than anything DARPA could do.
The beauty of weaponizing the weather is that it renders conventional nuclear shelters, worthless. We’ve read that the Chinese have developed thousands of miles of tunnels, stocked with supplies to withstand a nuclear strike for hundreds of millions. Whether that’s true or not, we can bet that they have built shelters for the 1000 or so head CCP elite, and those shelters would be underground, where water could be a real problem for them. Especially flood waters. Water is far more destructive than fire, in the long run.