i am suppose to go to port a this weekend but right now the weather is saying 30% of rain everyday for the next week. why is their that much of a chance everyday. should i cancel my hotel reservation?

Well, I' m not sure if you really want: a. a scientific explanation for precipitation, b. the methodology employed by meteorologists to formulate and publish their predictions on the likelihood of a precipitation event occurring in a particular locale, on a particular date, and at a particular time, and c. for us to decide for you whether you should cancel your trip or risk being present during a said precipitation event. Or, perhaps these were rhetorical questions and you just need a recommendation to bring an umbrella in the event it rains.

Or, maybe you were just making chit-chat.

Whichever, good luck with your trip! Unless you don't go.

I've got a place in Rockport, at this time of year those are mostly just scattered tropical thundershowers in the afternoon and usually last less than an hour of the day in total.

I'd still check the forecast to see if it is frontal related or a tropical system as that can be all day rain.