I think the issue is because of the ? after weather. The ? indicates the start of the parameter list, so you would need to specify the city and api key as the required parameters in order to get this request to work.
Tip: I always recommend building and testing REST requests in a third party tool (Talend, Postman, SOAPUI, etc.) before creating a connector in Orchestrator. That will help identify issues like this before you involve Orchestrator.