We recently purchased a pop-up camper, however, there have been many trips where we stayed in a tent. We ALWAYS brought along a window air condition unit to keep the tent cool. It works like a dream. You place it outside one of the windows with a tarp over it to keep the air blowing inside the tent (which also helps it look nice on the outside). I have also seen people cover their tent (& the canvas part on a pop-up) with a blanket that looks something like aluminum (I'm sure it has a name, but that's what it looks like to me) to reflect the sun off of the tent. We are trying this idea with the air conditioner Labor Day weekend.