A parked car, even in the shade: what a cabin-temperature study reveals for cats
"I'll only be five minutes" is the phrase that most often precedes a heatstroke in an animal left in a car. A study measured precisely how fast a car cabin heats up under different weather conditions, figures that speak for themselves for a cat being transported in summer. Find all our transport guidance in the cat travel and safety section.
What a landmark study shows
A study by Grundstein, Meentemeyer and Dowd, published in 2009 in the International Journal of Biometeorology, modelled the maximum temperature reached inside a parked vehicle's cabin under various weather conditions (study on Google Scholar). The results show that indoor temperature climbs very quickly even in mild weather, far exceeding the outdoor temperature within under an hour, and that the phenomenon stays significant even on cloudy or mild days. Cracking a window open only has a marginal effect on this temperature rise.
What this means for transporting a cat
- Cats regulate heat poorly, mainly by panting or grooming, mechanisms quickly overwhelmed in an overheated cabin.
- An outdoor temperature judged "bearable" guarantees nothing: the study shows the cabin can become dangerous even on overcast or cool days.
- A few minutes are enough for a carrier sitting in direct sun through the windows to reach a temperature far higher than the cabin itself.
How to transport a cat safely
The simplest rule remains never leaving a cat alone in a parked vehicle, even for a few minutes, even with windows cracked open. A well-ventilated hard carrier, positioned away from direct sunlight, already limits part of the risk during the trip, as our guide on flying with your cat covers when it comes to choosing a suitable carrier. For a longer trip in hot weather, our article on camping with a cat also covers the cooling gear worth packing.
Frequently asked questions
Is a cracked-open window enough to protect a cat in a car?
No, the study shows this measure has a very limited effect on how fast the cabin heats up.
Does the risk exist on cloudy days too?
Yes, the modelling shows a significant temperature rise even on mild or overcast days.
Where should the carrier go to limit this risk while driving?
Away from direct sunlight through the windows, on a seat rather than in a poorly ventilated boot. Find all our guides in the cat hub.
This guide is part of Planète Pets’s Cats universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.