A couple of interesting factiods - in the '70s, Ma Bell did a test on car colors and people's perceptions of how dirty they were - you might have noticed that they switched from Olive Drab to white...
I had a Dodge van with sliding door. The slider mechanisim was covered by a little white metal roof, and mine rusted out. After replacing it, I started looking around and observed that all the white ones were generally rusty underneath, whereas the darker ones generally weren't. I surmise the higher heat from the darker colors kept the underside condensation from forming so often and for so long, compared to the white.
A friend of mine who paints cars and is observant would walk around his neighborhood looking at various finishes and noted that the white cars would still have the morning dew on them for much longer than the dark cars.
There are tables for the heat absorbtion/radiation of the various colors, and it's hard to beat glossy white for cool.
I am in the process of constructing a portable PVC ridgeline so I can drape tarps above my
Scamp in summer. I had to look hard to find white tarps in the US (I think they carry them at Canadian Tire or one of the Canadian hardware store chains) and finally found an internet source.
Pete in the RatHaus