I am in Texas, and this is the first year I haven't let phals out on my terrace (under a tree)...but, other years thy have survived summer outdoors here...I think the humidity and air movement helped them. This year it is just too hot, so they are indoors, and the AC dries them out. I am watering mine more often, and using humidity trays underneath. They also have a fan nearby to keep air moving.
You repotted yours recently, didn't you? Were roots in good shape?