Do you have any references on the data provided by Apple to IBM, e.g. how can Apple provide live weather data for all possible locations without sending your location to IBM? Is the iPhone's IP address (which can be mapped to WiFi location) used to make the weather data request to IBM?
It would be reasonable to expect that as part of TWC’s contract with Apple, they’re contractually required to keep individual location data private. I wasn’t able to find any concrete evidence of this except for the TWC privacy policy for the Apple TV, which seems to explicitly differ from the normal TWC privacy policy in that it excludes the sale of individual-level data to advertisers. (If I’m reading this correctly.)
I don’t think that Apple has any technical privacy measures in place here, but I would be deeply surprised if, after all their pro-privacy advertising, they allowed a default app to be (at the contractual level) a giant privacy risk for their customers.