I just noticed that it's raining. Does this happen on a regular basis, or is this part of the Peka Boo event?

Were you here for the Tempest event? During that event Tempest (a bear) caused it to rain in some locations. It's possible this new rain event is connected or it might simply just be rain (to make the scenery a bit different).

Although I suspect the rain might cause something to happen in regards to the event.. we'll just have to wait and see. :)

Well, the page does change for night time. I think they may have just set it to be raining today for some variety. When you have outdoor festivals, sometimes it rains unexpectedly. They could be just trying to make it more interesting or realistic. I think it's cool.

I think it's a good idea too. I hope it ties in with the event, that would be fun

Tempest came to visit me (as a Random Event) and gave me a plushie, so my bet is that she's at the event having fun, too.