I live south of Houston, HEAT plus RAIN. I bought some of those window deflectors that cover a bit of the top inch and one half of the window, I thought I wouls hate them; but they are the best thing I bought! I can leave the windows down a couple inches, and rain won't come in. The car is WAY cooler- maybe 20 degrees! We have millions of mosquitoes- and they haven't come in like I expected. I didn't get the back window ones, but I will soon, since the battey is in back. ALSO, at any temp below 85 (as in most mornings) I can drive on the highway with no AC, windows all or partly down, and the deflectors make the interior much less gusty.
On top of all else, they look GOOD, and keep some sun out. I got the weathertech tinted ones, they mount securely without tape. Downside is; at the end of a hot day with windows down a bit, the plastic expands enough that the windows wont quite close without binding. As things cool with AC, they close.
Peter

Peter