Taking a step back, people are completely missing how China’s weather systems are different from the rest of the world. Although China is a smaller country than Canada or the US, they have an extremely dense urban and factory core along their west coast. Weather forecasting in China is inherently a more complicated task because they need to consider not only meteorological effects but those from human activity. China also uses many techniques to monitor bans on emissions for large events (most notably, the Beijing Olympics) and it’s almost certain that they would prefer to use cheap balloons than expensive satellites for that task.

A Chinese weather balloon can have a hell of a lot more sensors than a Western one because they do actually need to track human activity for forecasting. Given the population density of China, you would also need a whole lot of balloons to loiter in the sky.

What’s more likely? That China has some advanced weather forecasting system, or that they decided that satellites are a bit too expensive nowadays and they’re better off using balloons visible from amateur binoculars for spying on their largest rival?