http://www.tropicalweather.net/picts/honolulu_average_beach_water_temperature.jpg
Water temperature was in the upper 70s.
3 hours in that water temperature should not be a problem
Living in the desert I will not go in our pool unless the water temp. is at least 88 because of the low humidity. When we lived back east water temp. of 72 felt refreshing because of the higher humidity. Hawaii is pretty humid so water temp. of high 70's should feel pretty good. JMHO, for what it's worth.
