Body heat release?

[joxville]

Which is better to wear on a hot, sunny day to help lower body heat- a white T-shirt or black T-shirt?

[sn�gs]

black absorbs... white reflects...

[ACtheTROLL]

in mediterranean countries old ladies wear black
in Arab countries ladies wear black (gross oversimplification) - but the blokes wear white
in India/Pakistan ladies wear colourful saris
blokes wear white/grey

the common factor is they all wear loose clothing that covers almost all their bod

[beso]

While black can potentially radiate more heat in some circumstances it won't when exposed to the sun. Black absorbs more rasiation in the sun.

The direction of transfer depends on which source is hotter. The surface of the sun is about 6000 degrees Celcius. Your shirt is heated from below by your body to less than 37 degrees.

Even though the parts of your body not directly lit by the sun may be facing much cooler places the 6000 degree difference where the sun is present dominates so black clothes absorb more heat.

At night the temperature of radiation from a clear sky is below -200 degrees so the black would radiate more than white.

Having said that, most of the heat lost from the body is by direct conduction into the air and its subsequent convection away from the body. Hence cloths which allow air to move will do more to cool than anything about colour.