Today is 7th June 2017. Consider the following phrase
Questo sabato andiamo al mare
"This" Saturday is definitely interpreted by everyone as the 10th of June.
Now consider the following
Sabato prossimo andiamo al mare
"Next" Saturday is often both interpreted (by many speakers) as either the upcoming 10th Saturday or the one "next" to the upcoming (the 17th).
I really had troubles misunderstanding sentences like the second because the speaker meant "weekend of the next week" or "monday of next week" according to the specific context.
There is a hint that if the "next" day can be tomorrow or 8 days later, "next" mean 8 days later when talking about a weekday.
A giugno "prossimo" scadono gli interessi / Il "prossimo" giugno scadono gli interessi
The above can mean June 2017 if said in March 2017, but I found it being interpreted as June 2018 if the sentence is said in May 2017
What is the official grammar interpretation for "prossimo" when referring to a timeline?