I'm a new Windy user and while I love the features and visualisations, based on my first impressions I think the user experience could be improved.
Here are a few things that I noticed:
Having the hamburger menu icon at the bottom right hidden in the middle of several other icons seemed like a very odd location to me and took me a while to get used to. It still doesn't feel "right".
The app seems to have two "modes", one where you can change settings (layers etc), one where you can view and interact with a location's forecast. As a result I can't find a way to change the layer while viewing the forecast for a particular location. The "only one or the other, not both" behaviour between the forecast and menu system seems like an unnecessary limitation that could be fixed/improved? I currently seem to spend a lot of time jumping between the two. If there's already a way to do this, it's not at all obvious, at least not to me.
I know there's a lot of requests and discussion already but... Not being able to change the default layer (or in general, remember the app's state from when it was last used) is proving very frustrating! Changing layers (and rezooming the map) is always the first thing I have to do when I open the app. I even created an account thinking that might save my preferred layer etc, but no. I read that the reason is due to caching so the app loads quickly (and possibly to reduce data costs)? I can't help but wonder if that's a false economy though. For me it means I load the wind layer AND the cloud layer every time I use the app, and going by the comments/requests on here I can't be the only one. Have you thought about gathering statistics to see how often people change layers on startup, considered caching several of the most popular layers, etc to come up with a real solution for your users? The fact that people are using scripting apps as workarounds show what lengths sone will go to to overcome what is ultimately a usability issue with the application.
I hope you'll find my feedback helpful and take it in to consideration for future versions of the app. Thanks for a very useful application!