Έξω βρέχει - It's raining outside.
When you're talking about the weather, yes, βρέχει means "it's raining."
Το κινητό μου βράχηκε - My cellphone got wet.
Μην περπατάς σε βρεγμένο πάτωμα - Don't walk on a wet floor.
When you're not talking about the weather, βρέχομαι, as well as the adjective βρεγμένος-η-ο could be referring to anything. For example, the cellphone might have gotten wet because someone spilled water on it. The floor could be wet because it was just mopped. It doesn't always have to do with rain.
In this case, I guess someone could say that the rain is somehow implied, since this is the way most jackets get wet (xP), but we actually can't be sure about that. Plus, I don't think I've heard the phrase "Being rained up(on) too often for a piece of clothing that's exposed to rain. "Getting wet" seems just fine to me. ^.^
Thanks, Dimitra956826, for your response.
"getting rained on" is a very common expression in English.
Am I correct, then, to understand, from your response, that if I want to say that I am being rained on or that my jacket is being rained on or my book is being rained on, then I would say βρέχεται, with my jacket or the book as the subject? Thanks again.