My understanding is that the fabric on burqas (or whatever those clothes are actually called) are extremely lightweight and provide shade, so they actually aren’t any warmer than t-shirts and shorts. Possibly because they block the sun, they might even be cooler.
But that’s simply what I have heard and I personally don’t care to find out either way.
Wild guesses…
Easier to clean.
Or maybe the material it’s made of, isnt white.
Or maybe because it has such little thermal mass, that it doesn’t matter.
Or because they liked the colours for aesthetic reasons haha.
Also choosing a cloth colour has nothing to do with thermal mass and everything to do with absorbtivity/emissivity/reflectivity aka material properties affecting radiative heat transfer.
In any case, shirt colour has a small effect on temperature, maybe a 5°C (at most) difference between white and black, according to some studies. So unless you’re really chasing the most optimal clothing, it’s best to just wear what makes you happy.
I never tested it, but still wonder why nobody who wasn’t indoctrinated into it since birth doesn’t just decide to wear a burka in summer heat.
Not only did you not test it, you didn’t even bother looking it up, because you don’t actually care, you’re just here to express islamophobia.
Here, have the result of a 5 second search:
https://qz.com/766186/the-woman-behind-the-burkini-says-40-of-sales-are-to-non-muslims
I wonder how saying that Muslims are being exploited counts as islamophobia.