but like, here in the real world, farmers use weather derivatives. so the technology works, has a use case, is proven.

if your point is that one should not treat the market's number as some oracular probability, then... of course i agree! there is no such thing. the market provides a signal, like any other.

Not a farmer, but I believe they use weather derivatives to hedge and weather forecasts for predictions? Going through markets for weather forecasts is adding a level of indirection that generates a noisier signal.

The idea when hedging isn't to win on expected value. It's to reduce risk. You're paying the market to provide insurance.

As a side effect, insurance does sometimes generate interesting data. The insurance industry generates good data about life expectancy. But it doesn't tell you when you're going to die.