Hello again pk2200,
One of the reasons your question interested me is that I live in
Arizona, where almost ANYTHING left in a car in the summer, will melt
in minutes-Dry heat or not! Out here, they say, once it reaches 110
degrees, it is just plain unbearable...a rise in temperature of a few
more degrees is not detectable--we are already baked!!!
A few hot summers ago, a local television station ran an uncontrolled
experiment at a car dealer on this very topic. I can find no data or
reference to the "study", but they determined that lighter interiors
were cooler after an hour, by up to 10 degrees than the dark
I did find reference to Click and Clack "Car Talk" program's
discussion of this topic, but that was all it was, a reference. There
was no hard data to be found on their site.
What I DID find:
According to the National Safe Kids Organization, if the ambient
temperature is 79 degrees F, car interiors can reach the following
White Interior 135 degrees F
Red Interior 154 degrees F
Blue/Green Interior 165 degrees F
Black Interior 192 degrees F
In this 1995 study, interior temperatures on vehicles of dark blue
or light grey EXTERIORS were studied. The outside ambient temperature
was 93°F, and it was partly cloudy. Within 20 minutes, the interior
temperature in both cars exceeded 125°F.
In this study, the cars studied had stabilized temperatures of 120
degrees in two hours. The lighter cars took a bit longer to reach the
120 degree mark, but by the end of the two hours, the temperatures in
all vehicles were almost identical, and stable.( This is also
mentioned in unstable-gas comment below)
According to this CDC report, cars parked in direct sunlight can
reach internal temperatures up to 131 F-172 F (55 C-78 C) when outside
temperatures are 80 F-100 F (27 C-38 C) (6,7).
In at least two incidents during the summer of 1998, deaths occurred
in dark cars, and the dark color
The Dangers of Interior Heat
General heat absorption and cars. (This site has some broken links,
but the page has some interesting reading!)
Effects of heat on cars:
Hope this helps!
car interior + heat
auto interior + temperature