How hot does a car
get inside?
Short answer: On a hot sunny day, the air inside a closed parked car commonly reaches 115 to 140°F, and the dashboard can pass 150°F. Most of that rise happens in the first 30 minutes. Shade helps a lot. Cracked windows help an empty car a little, but never make it safe for a person or pet.
How fast a parked car heats up
Sunlight passes through the glass, heats the seats and dashboard, and that heat gets trapped inside. Research by Jan Null at San Jose State found the cabin warms by roughly 19°F in the first 10 minutes and about 29°F in 20 minutes, with around 80% of the total rise in the first half hour. That's on mild days too, not only in a heat wave.
So a 90°F afternoon can mean a cabin well past 120°F before you're back from a quick errand.
What the surfaces reach
Air temperature is only part of it. A 2018 Arizona State University study parked cars in the Phoenix summer sun for an hour and measured cabin air around 116°F, the dashboard around 157°F, the steering wheel around 127°F and the seats around 123°F. In shade, the same cars' cabins averaged about 100°F, and the dashboard about 118°F.
That's why the steering wheel and seat buckles burn even after the A/C has been running for a minute: the air cools fast, the surfaces don't.
Is a Tesla hotter than other cars?
Model 3 and Model Y have a large glass roof, which lets in more sunlight than a painted metal roof does, so they can heat a bit faster on a sunny day. Tesla offers Cabin Overheat Protection to cap the cabin near 105°F by running the A/C, which uses battery while it runs.
What changes how hot it gets
| Effect on cabin heat | Notes | |
|---|---|---|
| Parking in shade | Large | In the ASU study, cabin air was about 16°F cooler in shade. |
| Windshield sunshade | Moderate | Cuts heat through the windshield and keeps the dash and wheel cooler. |
| Cracking the windows | Small to moderate | Lets the hottest air escape, but the cabin stays far hotter than outside. |
| Light interior and tint | Small | Helps surfaces more than air temperature. |
| Running the A/C while parked | Large | Works, but uses battery the whole time it runs. |
Does cracking the windows help?
A little, for an empty car. Studies of parked cars, including Jan Null's, found that cracking the windows an inch or two barely slowed how fast the cabin heated up, and the inside still ended up far hotter than the outside air. A gap does let the hottest air near the roof escape, so the car is less of an oven when you get back in and the A/C has less heat to remove.
What it never does is make a car safe for a child or a pet. If anyone is inside, the car needs active cooling, such as Tesla's Dog Mode or Camp Mode, or they shouldn't be left at all.
For an empty Tesla on hot days
VentMode cracks your Tesla's windows when it's hot and dry where the car is parked, and closes them when rain is coming and every evening. It uses no battery while the windows are open. It's for the car sitting empty at work or in a lot. It is not a substitute for cooling when anyone is inside.
$29/year with a 7-day free trial.
Frequently asked questions
How hot does a car get inside on a 90 degree day?
In direct sun, a closed car can pass 120°F inside within about 30 minutes on a 90°F day, and keep climbing toward 130 to 140°F over the next hour. The dashboard gets hotter than the air.
How fast does a car heat up in the sun?
Fast. Research at San Jose State found roughly a 19°F rise in the first 10 minutes and about 80% of the total rise within the first 30 minutes.
How hot does a dashboard get?
In a 2018 Arizona State University study in the Phoenix summer, dashboards in sun-parked cars averaged around 157°F after an hour.
Does cracking car windows help with heat?
Only a little. It lets some hot air escape from an empty car, but the cabin still gets much hotter than outside. It is never safe for children or pets.
Does parking in the shade really help?
Yes. In the Arizona State study, cars in shade had cabin air around 100°F versus about 116°F in the sun, and much cooler dashboards.
Related: Cabin Overheat Protection, explained · What does Vent do in the Tesla app? · Tesla Dog Mode · Climate battery use
Keep the empty car from baking on hot days, with no battery cost.
VentMode is not affiliated with Tesla, Inc.