Several important issues currently--the water depth is good at Castle Rock cut--which saves about 10 miles of both a no wake zone, and some rough water as you go up lake. The water is dropping slowly, so we should still have plenty of water in a month.
This time of the year, the day high is in the very high 90's. Nights are low to mid 70's. Without AC the boat can get hot inside. You do want to have fans at the least.
Meade will be hotter, less good canyons to explore (unless they are of the slot machine type).
I would head over to Calif. Coast, launch at Sunset Aquetic Park in Sun Set Beach and go to Two Harbors at Catalina, tie up on the String line for a couple of weeks, while the houseboat crowds and PWC's clear out of Powell, and the temp drops.