I open mine on May 1st, and usually leave it open until Oct 1st. But it's usually only warm enough to swim(I'm cold natured, and I like it HOT - my friends joke that I have the world's biggest hot tub, because I keep it that warm), at least for me, from the end of May, until mid-September.
I really am going to try to not have 30 people a night, at my house. Last year's parties were rock star out of control. And NO ONE under 21, this year, either(no, I never invited them, but I'm too nice to throw people out).
Lord, if you'd seen how much booze we went through. Sometimes 2-3 1.75 litres of vodka and whiskey, a night!
It was so hot last summer, and I had ~the~ place to be, nearly every night. Pics from my pool, were on FB, of nearly everyone in my town. And while I'm generally a modest person, after 8 whiskey cokes, and someone yells, "suits off!!!", I just go with the flow. We did all observe the rule of, "no penetration in the pool".
Seriously. It was close to that a few times, and we all decided that that was crossing the line, even though we were all drunk and naked.
Take the pool sex, to the pool table!
TMIJTIS