Good morning Justin Richards,
The behavior you describe is not a configuration mistake on your side but a failure in how the World Clock and Weather web parts are resolving city data. Those web parts depend on Microsoft’s location service to populate the dropdown. When the service call does not return results, the spinner remains indefinitely. Clearing cache or switching browsers will not correct it if the service itself is failing.
To confirm, test from another tenant or account: if the same city search hangs, the issue is upstream. If it works elsewhere, then your tenant may have a restriction on external services or a blocked endpoint. In that case, check whether your firewall or proxy is preventing SharePoint from reaching the location service. If the problem is consistent across tenants, it is a service outage and requires escalation through Microsoft 365 Service Health.
In short, the dropdown not populating is caused either by a blocked call to the location service or a temporary outage in Microsoft’s backend. The resolution is not a local setting change but either allowing the traffic through your network or waiting for Microsoft to restore the service.
I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer then. Should you have more questions, feel free to leave a message. Have a nice day!
Vivian