How few layers you need in summer heat

Short answer: One layer is enough above twenty five degrees. Two layers can be cooler if the inner one is thin and the outer one is loose.

One layer in strong heat

When it is very hot, a single thin layer gives the skin the most air. Choose a loose fit so air can circulate, and a fibre that absorbs moisture and releases it to the air.

When two layers are cooler

In strong sun a loose outer layer can shade the skin and at the same time hold air between fabric and body. That is why people in hot countries often wear a loose shirt over a thin layer. See bamboo t-shirts for men.

The role of underwear in heat

A thin layer against the skin absorbs the sweat before it reaches the outer layer. That keeps the outer layer dry and prevents visible marks. See bamboo undershirts for men and bamboo underwear for women.

Frequently asked questions

Is it coolest without underwear

Rarely. Without a layer against the skin the outer layer gets wet and clings.

Do loose cuts help

Yes, more than colour. Air between fabric and skin is what cools.

What about long sleeves in the sun

A thin long sleeve can be cooler than bare skin in strong sun, because it shades.