It’s not pseudo-science. The science behind it is solid. But, weather is very chaotic. It’s known to work to a certain extent, but it has relatively minor effects, it’s very unpredictable, has unpredictable side effects, and is fairly expensive. All you’re really doing is slightly boosting the formation of ice crystals in the clouds by adding a material that will hopefully produce more nucleation sites. It works in a lab, but how well it works up in the atmosphere is unknown. It probably does something, but it’s very hard to get an estimate of your “bang for the buck”.

For example, Beijing tried it during the 2008 Olympics to reduce the chances of rain during the Olympic opening and closing ceremonies. There was a moderate chance of rain predicted to happen during the opening ceremony. The government launched more than 1000 rain dispersal rockets, and it didn’t rain during the opening ceremony. Did the rockets disperse the rain? Or did it simply not rain because that’s not how the clouds developed. Who can say?

It’s not pseudoscience.

a coordinated, State-funded program began in earnest in the latter half of the 1990s. Today, with drought a pending, if not ever-present, threat to the economy and well-being of Texans, rain enhancement projects flourish within large areas of Northwest, West, and South Texas. In fact, the seven cloud seeding projects today cover about 31 million acres

You can totally blast a cloud to make it drop out of the sky. I’m pretty sure we figured that out before airplanes