I've been fiddling with adding the weather as @keyspace suggested in the comments, and it's actually really easy. I've no modding experience whatsoever and I still made it work! :D

1. Navigate to the where Omicron mod is stored (as of right now, that should be <steam install folder>\steamapps\workshop\content\244850\1898681794\Data)
2. BACK UP the file PlanetGeneratorDefinitions.sbc
3. Navigate to where the default planet definitions for SE are stored (<steam install folder>\steamapps\common\SpaceEngineers\Content\Data)
4. Find and open the PlanetGeneratorDefinitions.sbc (editor with xml syntax highlighting will help you a lot, such as Notepad, Atom, Visual Studio Code, etc.)
5. Search the file for <!-- Alien Planet's Weather Settings -->
6. Copy all text starting from this point up to the first </WeatherGenerators> tag
7. Open the Omicron folder's PlanetGeneratorDefinitions.sbc file and scroll all the way to the end
8. Towards the end, there is a line with <MinimumSurfaceLayerDepth>5</MinimumSurfaceLayerDepth> followed by a line with </Definitions> - paste the text in between those two lines (probably make some newlines to make it more organized, but as long as you don't change anything inside any of the tags, you're gonna be fine)
9. Save the file and boot your game

Make sure not to confuse the two files! It's easy to copy text into the wrong file because of the identical names and very similar contents.

I feel like there's not much room to go wrong with this, but I'll say it nonetheless - you're manipulating the game data in a non-standard way, so do this at your own risk. If you wanna be extra safe, backup your save files too, as the game itself can be repaired using the Steam tools.

If there's anything wrong in this, let me know and I change it (or delete this if it's way too bad...).