Having multiple oracles doesn't really change the problem, then you're implicitly trusting a group of oracles instead of just one.

With multiple oracles and a statistic, you're trusting their results to be distributed along some distribution. But I'm being pedantic. Ultimately, yes, you are still trusting the oracles even if you aren't trusting them each in totality. Like I said I don't think there's a way out. Even if you hook up a weather sensor machine and push updates to the chain, even outside of malicious tampering, sensors themselves can be inaccurate or fail. Perhaps there's a case to be made for an autonomous weather sensor machine that is physically tamper-proof, but ultimately there's a certain amount of trust when dealing with off-chain data. I don't think that's able to be overcome.