Summer heat does delay the blooming process... in all plants, hydrangeas included. I know I see that in early to mid June when our temps regularly hit above 95 and the roses stop blooming as often as they did before. I sugest not deadheading whatever bloomage you now have until things cool down a bit (normally, deadheading will encourage new blooms). You could even leave the existing blooms alone until winter if you so preferred; they tend to fall off on their own starting around February or later. About every how many weeks was the plant reblooming this time of the year for you?

I start deadheading this time of year. Like Luis said, it encourages new blooms.

Thanks for responding Luis and Natal, It must be the heat as it has been in the upper 90's for weeks. I actually had already deadheaded all the blooms before I posted. Hopefully they will bloom again this summer. We are supposed to get cooler temps next week!