I suspect in warm climates, the sun will save you the trouble of the defroster, especially if they fit it in the morning when it is cooler and you come back in the late afternoon when the car is at its hottest to reduce the vacuum pressure and the seal rubber at its most pliable due to the heat.

If parked outdoors.

One of the OU pictures in the article shows indoor parking.

I’m the wacko that leaves the windows open a crack if it’s sunny enough and not going to rain.

I doubt the defroster trick is as much about expanding what little air is left under the suction cup and more about making the rubber plyable enough to lift an edge enough to break the seal. So summer should be quite a bit easier.

The animosity towards OU parking is real. When I was there 15 years ago, the big deal was that fines were cheaper than a pass, so why bother? Parking costs are crazy for a suburban school, and parking enforcement is used as a money maker. Last I checked, they were building buildings in parking lots without replacing those spaces. <insert rant on the issues of higher ed financing>