I'm using MetaWeather api for this project, because it provides https and doesn't require an auth key.
CORS-Requests failed everytime, luckily I found a great extension for Chrome (Access-Control-Alow-Origin), it adds the header to the request, so that I can use it without a server (Development environment).
By trying to use best practices, I've added React-Redux to manage the place and date of the app everywhere.