I've been working on cloud textures for about 3 months or so and done some unique weathers and lighting types. There are many cloud types I want to make before I feel "finished". Cirrus is pretty much finished, but there are more ones to do in cumulus and rainy/overcast clouds. Cumulus are the hardest ones and takes the longest time, but the rest goes pretty fast and easy.
So, I don't really know when it will be finished, but I continue to do them because I find it fun. If I realize it will take too much time for me to ever get finished, I'll release the textures as a resource package or as a very small mod to just replace vanilla weather and not create hundreds of new ones

Or I'll send them to someone else who creates a weather mod and let them incorporate them in their mod. In one way or another, you'll be able to see them in your game. Hopefully it won't take too long!