We are making good progress so far, here the feature list, the ones with a 👍 are implemented.
Rain affects critter and fish spawns 👍
New Rain-exclusive fish and critters 👍
Unique rain ambiance for light-mid-heavy 👍
Rain lowers Temperature (greenhouse immune) 👍
Rain waters crop tiles (outdoors only) 👍
Weather forecast (right now rain only happens through debugger commands)
Skybox changes (clouds will gather before rain)
NPC Rain Behavior
Then comes testing and bugfixes.
We are still deciding if we will add snow or not on this update, it depends how long it will take to fine tune the rain and redo the skybox to allow for proper clouds.