The accuracy of weather data has been largely unaffected since DOGE took hold. The reliability of the infra, however, has suffered somewhat. There are more outages now than there ever were, with a massive spike in outages, not kidding, the month DOGE was at its peak. At that time we even saw significant manifest changes - stupid stuff like clearly LLM-generated json fields that were whole sentences instead of the key/value pairs from the schema. It was a wild time.
Anyway downstream we're mostly fine nowadays. I can still follow storm tracks accurately, see real time responses, correlate with pilot reports and lightning strikes, compare with aircraft telemetry mostly favorably, etc etc. It's quite remarkable what high-end weather products are able to do, the ones you have to work for.
We do, however, merge several free/paid sources into one picture. Rarely do I find serious disagreement, but it does happen.