A serious question about backseat etiquette

You get in the backseat of a car. Maybe it's an Uber, maybe it's your friend driving, maybe it's your spouse.

It's summertime, and it's hot.

The driver starts fiddling with whatever it is they're fiddling with.

Serious question: how long do you wait to say, "can I get some air back here?"

Because I swear to god, I feel like I'm going to die in the back while they're up in the front seat using a napkin to clean up something in a cupholder, or whatever.

I have no patience and I last about three seconds once the door is closed and I have observed that there's no urgency in the front to accommodate the climate in the back.

How many beats do you wait before speaking up?