I for one think you are just fine. You aren't doing anything I haven't done for years in the past.
I keep my chams out like this each summer 24/7 all summer long. I bring them out in the spring when night temps are above 50 and return them indoors in the fall when night temps drop below 50. In between they never come in whatever the weather.
Normally our temps max out around 90- most days are 84-88. Less than a handful of days reach 90 or above.
This year our temps are only occasionally in the 80s. Most days are 90 and above! Many days are 95, and the last 3 days have been 98! We have already had 3 or 4 98 days this summer prior to these 3. This is unheard of for my area and is the most extreme situation I have experienced with lizards. It has been going on like this since late May!
All of my chams are out as usual (along with lots and lots of other lizards) and are doing great. I still have several of the mellers that hatched in December, my adult pair of breeder melleri, another 8 recently imported adult melleri that I aquired several weeks ago, a pair of young panther chameleons about 4- 5 inches long, and my son's pair of veiled chameleons.
They are all doing great.
The important thing is to keep 4 microclimates in the terraria- shade and misty, shade and dry, sunny and misty, and sunny and dry. This gives the lizards choices- the don't have to be constantly damp, they don't have to be sunny and wet, or shady and wet or sunny and dry or shady and wet, etc. They can be whatever they want and need. As you noticed- even the dry parts of the terraria are cooled from the cooling action of the mist.
I leave the misters on usually from 1-5 or 6, but this year many days the misters are on before noon and not off until dusk or even dark because of the ambient heat.