Yes, you'll need Air conditioning!!
Even with A/C, wife hated the Pop Up because she woke sweating from the green house affect of the sun beating down on the bunkend.
I have to agree with her, but it doesn't bother me that much since I like tent camping, which she hates. The heat literally beats down on your face in the bunkend while the air conditioning is blowing. The joys of sleeping under a tent. :)
When sitting in the main box, with all the windows open, it's like sitting outside. So if you don't do good outside in the 90s and low 100s, you'll still need A/C.
If your like us, and don't live in the sweltering heat, you'll need A/C. Our preferred temps are 60 - 80 degrees. Anything in the 80s and above is HOT!