Hi we were in Salou last year at the end of May & first week in June, we had great weather apart from 2 or 3 very strong windy days in our first week, I can only remember it raining overnight on our very first night and for one day nearer the end of the hol, the rest of the time was dry and sunny, temps got up to about 25 ish, it was a lovely holiday, only thing was it got very chilly at night and we always needed a light cardy or sweat top (in fact I lost the one and only cardy I had taken with me and It was so cold once the sun went down that I trawled the streets of Salou to find a replacement- it was actually quite difficult to find a warm sweater/cardigan over there!) Hope you have a great holiday, just remember to take a light jacket