Everyone who rides a bike eventually learns that wearing a jersey works better than riding shirtless.

First, skin cancer is a thing.

Second, jerseys (plus undershirt, for me at least) are hot for about 30 to 45 minutes at most. Thereafter, your body adjusts to the conditions, such that you sweat enough to maintain core temperature at the same level as if you were not wearing a shirt.

This assumes that you drink enough water and are moving through the air at a good rate. Cycling that way while wearing a jersey keeps you cooler than walking while shirtless.