Indeed the API would have to have changed on open-meteo. Alternatively, it’s also possible that open-meteo started blocking Tor (the only network I will use).
I doubt it’s a Tor block though, because of this other problem: when I first installed Breezy Weather, I configured it to get weather for 6 different cities. It all worked for a while. I could switch to any of the 6 cities and it would fetch the weather. Then after a couple months it failed to fetch 5 of the cities (luckily the cities I did not live in). Now it fails to grab weather for any city. BW indicates an error-free fetch “0 mins ago”, but shows no data. In fact, I’m calling it a software bug because BW is likely failing to show the user an error.
So it looks like two problems: OM changing their API and BW not reporting an error.