At what temperature is it worth running shirtless?

Today: 75F + 92% Humidity = Shirtless

Unashamedly, unabashedly, unapologetically.

Depends if you’ve crossed the threshold of nip chafing. If not, shirtless in warm sounds fine.

If blood is drawn on a 2 mile run anything over 40F is shirtless. Below that it’s worth taping up.

I’m in Aus. Sunny and 17C in late autumn here today and I’m tempted to ditch the shirt while I still can..

I live in Valencia and don't run shirtless ever. It's just socially acceptable here unless you are out on the beach or up on trials in the hills with no one around (and then it might be seen as sketchy). Summer temps are e regularly above 35 and it is humid.

Not socially acceptable

I live in Titicaca and it’s socially required to run topless irrespective of sex and to shed droppings while running as a donation back to mother earth from whence you came.

In the 70s there was what I considered an old guy, 40 years plus, from York, Pa. called Ben Hyser. I'd see him at races in central Pa. and the DC area. He NEVER wore anything other than shoes and shorts. Even in long races with temperatures in the teens that's all he had on. Well maybe he wore socks too.

I find it's more about the humidity.

That said, 70f+ and cloudy = warm enough to lose the top. 60f + sunny I can be convinced to go shirtless too.

As far as I'm concerned, every day is a good day to run shirtless.