[XorNot]

While generally true, it's worth remembering that thin shirts can have an SPF as low as 50 or so, which isn't much.

[hollerith]

It means only 2% of the harmful rays (UVA) are getting through the shirt or alternatively the skin under the shirt can spend 50 times as long in the sun as it could without any protection.

[hollerith]

Correction: UVB, not UVA.

Correction: the standard used for clothing is UPF, not SPF. They're similar, but there are differences.

[kube-system]

SPF is logarithmic so high numbers can be misleading. The FDA has recently banned labeling above SPF 60 for this reason. Doctors usually recommend 30

[tabletcorry]

A typical tshirt is closer to SPF 7, depending on color and weight.

[omnimus]

Just from basic logic this has to be false. Maybe there are some translucent t-shirts that are SPF 7 but my skin always reacts much more to sun exposed parts that have SPF applied than it ever did under t-shirt. And no i use high quality SPF50 and reapply.

[hollerith]

That sounds right, but SPF 50 shirts are readily available, and at least the ones made from polyester are cheap.