OK, at the risk of asking a stupid question, here goes – does a black or other dark-colored helmet absorb heat more than a white or light-colored helmet? It sounds silly, but strangely logical. After all, if you could pick between sitting on a car with a black car seat or a white one, after the cars have been in the sun, which would you pick? So, does helmet color correlate to head heat when you’re out in the sun for a long time?
And yes, of course, I understand that ultimately, the most important factor is that the helmet matches the color scheme of the whole bike/clothing ensemble… 
I ONLY ride white helmets. Styrofoam is a TREMENDOUS insulator, so it probably makes a minimal difference. Combined with all the vents on most helmets, it would also be hard to build up heat… So probably on most helmets, a black helmet won’t be any hotter. But it certainly won’t be any cooler, so why do it? (I know, I know , the matching…)
HOWEVER, with aero helmets, that have a fair amount of relatively “dead” air underneath, I’d imagine there could be quite a noticable difference. Certainly a black aero helmet seems like foolishness to me.
I am justified!! Thanks Gary. I always felt like such a geek. Now I know that I am a geek, but at least I’m correct in my geekiness!
Thanks, Gary and Rappstar. Is there anything that ST’ers don’t know, and don’t post awfully quickly?
I ONLY ride white helmets.
Now, white shorts are a different matter…
Not really. I got my rowing team white unisuits for our senior year in college. We were much cooler in hot weather races as a result. David Millar rocks the white bibs. And for sure if I raced in Kona, I’d find a way to get some white shorts. I mean, it’d probably be better if there was some extra material up front (as the company that made our unisuits did, WITHOUT being asked to… I guess they just knew… Especially with the rowing tradition of jumping in the water after you win…), but it isn’t necessary.
Heat-wise, you’re right – I was just joking about all the posts (and some pics) of why not to wear white shorts due to the, ahem, “visibility” issues in front…