Thanks for pointing out my typo. However, the iptcDict still doesn't have the caption data. I don't think there's a public API available to access this data.

Hi Bill. Nope. Still not possible. Let me know if you figure out a solution. Thanks!

I'm having the exact same issue. I following the setup steps (checked both boxes on the developer website), added the WeatherKit capability to the app. It's been about 2 hours and still getting the 401.