Thanks for the comments!
@Sergio: Glad you liked it! It was supposed to be a sunset landscape, hence the sun being placed on the left side (although this is very shaky reasoning, since the perspective here is inherently wrong), but simply flipping the picture horizontally should do the trick. Also, if we take into account that I spend ~99% of my time indoors, it wouldn't surprise me if the sun had somehow turned green years ago and I just hadn't still noticed, so my depiction may not be the most accurate anyways
@canteven: I started adding shading tiles to pretty much all of my tilesets, because they can add a lot of detail to a screen without requiring multiple variations of the same tiles. I didn't want to use transparent tiles for this set, since I felt that would defeat the purpose of trying to emulate the "pure" 16-color style, so I went for a dithering-based approach this time. I'm not 100% sure the white tiles were worth including, though. Maybe I could have used that space for more ornaments or maybe some grass-covered mountains.
In other news, I added some more detail to the clouds in the "day" background.