Dog in parked vehicle - Considerations
Sorry but I am more worried about your dog being left in the car for an hour:redcard:
Some time back I had to smash a car window to get a heat suffering dog out that had been left in a car and that was a relevant coolish day, it wasnt a very pleasant sight, so please be aware of the consequences and act accordingly, please:nonono:
As long as you take proper precautions, this shouldn't be an issue.
The most common mistake made in this regards, is to completely shut the windows, thus not providing possibilities for the heat to escape.
On a couple of occasions, I actually had to lend tools to the police so they could lawfully break into car in order to cool down a suffering poochie.
Animal welfare law where I lived at the time (Norway) allows them to do so.
Thread starter seems to be aware of the pitfalls, and seems to have thought of further precautions as well:
Having to leave the dog in the car tomorrow for about an hour at the most, windows slightly open and parked in shade with water on the floor.
With these precautions, heat will be able to escape from the car, the dog has water, to prevent dehydration,
and the car should have shade enough to not get hot in the first place, with a little prediction of where the sun will shine for the next hour.
In addition, I'd recommend getting a couple of adjustable ventilation lattices, that can be tucked in the rear window frames.
Just open the windows, adjust them to the width of the window, and raise the window glass to securely jamb them into place.
This will allow even more heat to escape (and when there's a slight breeze, even more cool air to be drawn in).