Foggy and Overcast Weather

What I want:
I want two new weather types added. Foggy weather and overcast weather.

Why I want it:
It would add more immersive atmosphere to the game and break up the weather a bit more so it's not just rain, thunder and clear. The added variety would just be nice to see.

How I want it to be:
Overcast would just be like the visuals seen in dry biomes during rain but a bit brighter and in all biomes.

Foggy weather would push the distance fog closer to the player and apply a screen filter like the one during rain. The general coloration of the sky would look similar to overcast.

These different weathers wouldn't effect spawning above ground regarding hostile mobs.