maybe the new environmental “event” in summer.

[Yuni]

On the 5th day in summer, there is green rain and TV does not work. I was totally shocked and thought it was bug caused by version updating, until I found the information when talk to NPC.

[Sha of Insanity]

I am seeing the new green rain event too! It was stating on the weather channel the day before that "Um... There appears to be some kind of... anomalous reading... I... don't know what this means..." My trees are warped and covered in moss :)

[Clovis Sangrail]

So what was the point of this event?

I hadn't played in awhile, and apparently, I started a new game the day the new update dropped. There's all kinds of new stuff that's not even documented yet, and this green rain is one of them.

I now have tons of moss and some kind of rare green tree seed. What do I do with them?

[Radiosity]

Moss is a new item required for some recipes, so that would seem to be one way you get the item.

[Charby]

Originally posted by Yuni:

On the 5th day in summer, there is green rain and TV does not work. I was totally shocked and thought it was bug caused by version updating, until I found the information when talk to NPC.

The date seems random, I got it on the 14th day of summer.