Is darker clothing warmer on a summer day and vice versa?

[threemae]

My Google-fu has failed me, and although I’ve tried extensively to search through the archives, I’m not sure that this question has ever arisen on these boards:

Is lighter colored clothing cooler than dark colored clothing on a hot day?

I ask because the search and rescue agency that I work with is designing a new shirt and the battle is on between “navy” and “royal” blue. One arguement used on behalf of the lighter shade is that it will prove cooler for very warm summer days. I vaguely recall hearing from another source that light and dark colored clothing is actually close to equal in terms of heat because dark fabrics absorb more infrared radiation away from the wearer. I’m sticking up for this argument just because I think the darker blue looks much more professional.

Looking towards people that oughta know, I find mixed results, supporting my claim of their relative heat level for the wearer being equal. Some people that live in the desert and are a part of cultures that have been surviving there for thousands of years wear bright white clothing:
http://www.raphaelk.co.uk/web%20pics/Israel/first/Bedouin%20Camp.jpg

Others don’t:
http://www.hrc.utexas.edu/exhibitions/online/ddd/gallery/islam/369.html

And a mix:
http://www.unc.edu/depts/diplomat/AD_Issues/images_17/niger/14-Tuaregs_at_flamme

So, Dopers, what would ya’ll say about the relative warmth of light or dark clothing?

If you guys don’t like this one, I suppose I’ve got a plane on a Nordic-skier that we could talk about.

[threemae]

Apologies, broken third URL:

http://www.unc.edu/depts/diplomat/AD_Issues/amdipl_17/letters/nigerpix/sahara14.html

[Sam_Lowry]

Here is a Straight Dope Staff answer to the question. It seems that it depends on the color of the clothes, as well as how tight or loose fitting they are and how windy the weather is.

[CookingWithGas]

@Sam Lowry

Here is a Straight Dope Staff answer to the question.

With all due respect to Doug, I do not see how he leaps from a study of bird plumage to humans in cloth. Further he says:

. . .black clothing absorbs sunlight and the heat radiating from your body, but if it is loose-fitting, and there is wind, the wind convects the heat away faster than it is absorbed.

I do not quite understand the phrase “absorbs sunlight” since what it does it absorb light and re-radiate it as heat. Ask any barefoot kid this summer if he’d rather walk on the white sidewalk or the black asphalt.

White clothing reflects sunlight, but also reflects internal heat back towards your body, so the net effect under identical conditions is less cooling than if you wore black.

I don’t understand the significance of reflecting “internal heat back towards your body.” Convection would seem to me to be a much larger factor in human cooling than radiation. And radiation from the sun in direct sunlight would have a very large effect on heating a human that heat from ambient air. This is from my personal experience as a human.

The bedouins may have cultural imperatives that are unrelated to how comfortable black clothing is in hot climates. This is true of Saudi women who wear black and are veiled.

All that being said, there probably isn’t that much difference between navy and royal blue.