Rainy days quick shelter

I’ve been checking information about many different kinds of shelters, but when thinking about it, always the same image cames to my mind: What if you get to some place and has been raining for weeks, so everything is soaking wet???
I mean, for example in youtube most of the videos about shelters are recorded in more or less sunny days (or maybe i didn’t make a deep enough research)
what kind of quick shelter could you build in this kind of scenario?? any ideas?