The Green rain weather event is one of the new additions to Stardew Valley's 1.6 update. As the name suggests, it's a rare type of weather that literally brings a green glow to the town, along with several rare materials to gather. It's a great time to stock up on moss and the far more common fiber if you happen to be low on those particular resources.

So how can you take advantage of the new weather phenomenon? In this guide, I'll explain when the green rain can happen, what to look out for when it does, and how to tell ahead of time that it's coming so you can prepare for it.

Stardew Valley green rain: When does it happen? 

Green rain can only happen during the summer, and even then, it's a very rare occurrence. There is no real warning that it's coming, except the weather report on your TV will tell you that there's “some kind of anomalous reading” the day before. When that happens, it's your cue to prepare plenty of inventory space and clear your schedule for the following day. 

What can you gather during green rain? 

When you step outside on the morning of the green rain, you'll notice everything looks noticeably greener and there are weeds everywhere. As well as regular weeds, you'll also find slightly bigger and tougher varieties have sprouted up too. These generally take an extra whack of the scythe and will mostly yield moss, though other drops are possible too. 

Here's what I've managed to collect from these green rain weeds:

• Fiber
• Moss
• Mossy seeds
• Mixed seeds
• Mixed flower seeds

As well as the materials above, you can also gather Fiddlehead Fern by chopping down the tall vines that you'll find in random places throughout the town. These might take a bit of searching to locate, but you should find more than enough to stock up on a good amount of the rare material.

As green rain only ever lasts for a day, make sure you've gathered everything you wanted before calling it—you don't know when the next one will be along.