[Android Apps and Games] MysteryIII:
I already tried some different Weather Apps and chose Weather & Clock Widget in the end. While I think it's only an average App when it comes to weather itself, it's pretty good in design and (multi-)functionality. You might take a look into it for some ideas. What I like most about it is the Widget.

For in-App design:

it's pretty common to organize hourly, 2/3-days, week and whatever forecast into tabs. You should add them to the burger menu before your current stuff and put a dividing line between.

alternatively add an 3-dot menu to the top right and push (most of) your current menu stuff there

hourly forecast would be nice as this is the most accurate forecast and you might decide daily events based on it, like making a barbecue (and therefore buying stuff for it) or meeting with somebody in a park or cinema; or just in which order you will do your plans

adding advanced auto-update features: based on your current country or service, you may have more or less volume to share, so you might to wish to:

set hourly updates if you have more than enough volume

set to (half) daily updates if you can only afford very low volume

set to only update on WiFi (especially interesting during roaming) as you wish to see new weather data as soon as possible without the need of using the own volume

Moon phase would be another nice feature

UV Index would be another nice feature

For Widget, as I can't use it I can only make assumption based on pictures and descriptions, my suggestions are the following:

add different kind of minimalist widgets and different designs of big widgets including (most of) these features:

integrate clock with different designs

integrate calendar events (nice advanced option: choose if you want to have all, only birthdays or chosen calendar)

hourly view

daily view

weekly view

previous options with or without clock and/or calendar events

different events based on where you click on the widget (preferable if you can choose the app) (that's the feature I like most):

on clock opens clock app

on event/date opens calendar app

on currently weather opens hourly forecast

(on next day, the day after opens 2-/3 days forecast)

on forecast day opens weekly forecast

change current location on click of location name

add one minimalist and one advanced widget with each having setup like PowerAmp instead of many preconfigured widgets

A general suggestion: as your App is in the starting phase of development (I would call it "beta") you should upload full version for free on xda and give promotion codes (for later need/end of beta phase) for helpful people only.

This way more people are interested in helping you and the ones that were really useful are not annoyed of missing limited promotion codes.

Ones you are at the point you would call your App completed, you can remove the full versions or update only "free version" and might give some additional codes away for promotion of the completed app.

Maybe giving one or two more features for free in a xda version (than in Play version) would be nice, just to support the idea of xda (helping each other).

I know that's quite a lot to implement (if you really wish to), so it won't happen just with the next update, but as I said I already used some different weather Apps in search of something with accurate weather data but also being useful, handy and functional. This is about what I was missing in one App or the other and with these suggestions you can satisfy both: minimalist and people looking for most advanced stuff.

So keep up your work and good luck, getting into XDA News is quite the good start ;)