I have been going to HHI for 40+ years, and have been a multiple timeshare owner there for more than a decade. We only live 2.5 hrs from HHI (it's slightly southeast), so basically our weather is the same as that at HHI. We never go for a whole week in May, BUT we ALWAYS are there for Memorial Day weekend...sort of a last-minute thing each year, and we simply rent something. Kids are not totally out of school yet, so we cannot spend the whole week. ANYWAY, May can be very very iffy, and if a cold front (or even a "cool front", is moving thru, you will never even think about going into the water , definitely NOT in the ocean (which warms up during June only) and only in the heated pools. Regular pools? NOT. Our kids have tried to use the outdoor pools during Mem. Day weekend many times, and it's just too cool...they have blue lips and are shaking. fun? maybe for them, but they're cold and just won't admit it, but it's obvious. They're afraid the adults will make them get out and go inside, so they smile and shake! The only option, then, would be to stay at a resort where there's an indoor pool, like Marriott's Barony or Grande Ocean...then it doesn't matter. So, don't be disappointed if you do have a very cool week there , even at the end of May. Even without that cold front, the ocean is not yet swimmable, unless you're from Vermont or something and are cold-blooded. I seldom see folks in the ocean in May...only those geting their ankles wet while walking along in the surf. And the pools? Only if heated!!!! Hottubs? yes. And there are very few of those who venture into the heated pools because of the breezes above water. Very few. May is a great time for sports, like golf and tennis and biking, but not for water stuff. I have lived my whole life within 2.5 hrs of HHI, and I know the temps, and anything from April to May can be very iffy. The very coldest week we EVER had there was once during the first week of April. Too cold to even get out and walk on the beach. We tried to attend the Heritage Golf Tournament, but we froze and had to leave. May is pleasant in general, but definitely NOT warm....at least, not by southern standards. Of course, Ohioians and Chicago/Pittsburgers love it no matter. It's all relative. but be prepared . Just a warning. It's NOT pool weather just yet. Only young kids with blue lips. Good luck anyway. jme