Open the window on the passenger side door for about 2 inches.
Rapidly open and close the drivers side door a few times.
The opening and closing of the doors makes sure the air gets pushed and pulled out of the car.
On a hot day, most of the heat forms by getting trapped inside your car.
So when the cars inside air gets to be the same temperature as the outside air, the temperature has dropped a few degrees.
As to cooling it down even more, dangle icecubes in small bags in front of your blower exhausts.
lifehacks.stackexchange.com/users/128/RichardBernards
If the AC is gone and your stuck in traffic there is really no good way to keep the car cooler outside of keeping the windows open.
However the way to have a car as cool as possible is to keep the car cooler when you are parked.
Park in the shade if possible.
Leave windows cracked, or open if your car is in a safe place and use a solar shield in the windshield.
Window tinting also helps to keep the car cooler, however window tinting often has local regulations about how dark it can be.
lifehacks.stackexchange.com/users/117/Jon
A couple of options to just cool yourself, and not the whole vehicle: If it's a short journey, wet your hair and ears beforehand with cold water.
Your ears contain a large quantity of blood vessels and are very sensitive to heat.
The best way of cooling yourself is to cool the arteries in your wrists, but that is typically more complicated to do while driving.
Wrapping a cold cloth around them could help, but wet hair and ears is much less obstructive to your ability to drive.
Another alternative is to cool your face with a small personal fan, consider attaching it to the dashboard and point it at your face.
Be sure to keep it far enough away that the air doesn't force you to close your eyes while driving though,
lifehacks.stackexchange.com/users/144/Nick Udell
If you have a converter, there's really no need to work around not having an air conditioner in your car, as long as you can run a fan you can make your own air conditioner .
Basically what you want to do is take two different-sized containers (one has to fit inside the other).
In the larger container you want to cut out a hole in the top so that you can set the fan on it and have air blowing into the container.
, and a few small holes in the side so that air can escape.
Then, you take the smaller container, and fill it with ice.
Simply place the container with ice into the larger container, then set the fan on top and turn it on.
The fan will blow air over the ice which cools it, and the air will escape out the sides of the container.
source
lifehacks.stackexchange.com/users/8/GimmeTehRepz
Carry a spray bottle of water.
When you first get in, spray it on dash, seats, steering wheel, & other too-hot-to-touch parts.
Then when you get hot while driving, spray it on yourself.
lifehacks.stackexchange.com/users/1722/jamesqf
Car shade Rain guards
I've been combining these two techniques for years.
The car shade stops your car from turning into a greenhouse and it keeps UV light from damaging your dashboard.
I use it even in winter.
The rain guards mean you can habitually crack the windows without worrying about the forecast.
They let any heat that does build up vent naturally
and it makes the fact that your windows are cracked less visible.
Makes me feel a little more secure.
Even on the hottest days I've never been uncomfortable getting in the car so long as I remembered to use these.
They certainly beat my old hack of rolling down the windows and driving like a maniac until the AC kicked in.
lifehacks.stackexchange.com/users/13771/candied_orange
Best way is to get the powerful 12V electronic Car use Cooling fan.
I have the Abovetek two heads car air fan from https://www.amazon.com/dp/B010CESJTC , it works so well to quickly blow away the hot air from summer parking car.
Two heads are 360 degree rotatable so it helps to cool you down and at the same time cool your pet down, isn't cool.
The cord is long enough
so you can put the fan at the arm rest area to cover both front seat and back seat, FYI.
lifehacks.stackexchange.com/users/15464/Yannies
Assuming your air conditioning doesn't work, how can you get the interior of your car to cool down?  Especially in traffic jams, where the car isn't moving very quickly.   I want to cool the interior of my car.  Ship groceries at a reasonable temperature.  Travel with my pets  Make it more comfortable for me and my passengers   I tried the the usual stuff:   Blowers on cold, but this is irritating my eyes  Windows open, works but in traffic jams it's barely helpfull.
How can you get your car as cool as possible on a hot summer day without air conditioning?
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<temperature><car><comfort><summer>
lifehacks.stackexchange.com/questions/1529
lifehacks.stackexchange.com/users/1206/Kevin
It can be very difficult to keep the interior of a car cool if you don't have air conditioning. However, slightly opening the passenger side window and repeatedly opening and closing the driver's side window can help. Alternatively, you could spray hot parts of the interior with a water spray or buy a car shade or cooling fan. The options are to change the air by opening the passenger side window 2 inches and then opening and closing the drivers door rapidly, dangling ice cubes in front of the fan outlets, park in the shade to avoid the vehicle heating up, try tinted windows, wet your hair and ears with cold water, place a fan on the dashboard, make your own air conditioner, carry a spray bottle with water and spray yourself as required or use a combination of car shade and rain guards.
Try opening the passenger side window 2 inches then open and close the drivers side door a few times to change the air. You could also dangle ice cubes in front of the fan outlets. To avoid the car getting hot in the first place park in the shade, and you could also try tinted windows. Wet your hair and ears with cold water and you could also put a small fan on the dashboard. You can make your own air conditioner in the car by getting a fan and blow air through a container filled with ice. Carry a spray bottle of water and keep spraying yourself when hot. Use a combination of car shade and rain guards. Buy a car cooling fan which can rotate through 360 degrees and keep everyone cool.