Ok, I think it is related to Adguard Home. I run all of my network through this and a recent update seems to have caused issues. I see a post on the home assistant GitHub about others having issues. Turning off Adguard did allow the page to load but then it seems to load fine from now on regardless of whether Adguard is running. So I can’t definitively point to this as the issue.
But while playing with this I noticed the API keys I have don’t support 3.0. And according to emails that OpenWeather is sending out the 2.5 API is being shut down in June and you need to provide a credit card for 3.0 API access with 1000 free hits a day. This may have been discussed elsewhere but I couldn’t find anything on this. I am going to register but curious how many hits this tile is making to the API per day?