Sorry for replying so late. The fabric is very much in-between, but I'd say wearing it feels more than a jacket than a shirt. That's highly subjective of course. The fabric is "high count", meaning it's not letting a lot of air in and out, so if you live in a humid summery climate (like California or Japan), it would be definitely too warm. I expect to be wearing it here in Tokyo until around May and then from November onwards. It's just too damn humid in this city. It'd be very good for central and northern European summers, though Yes, the colour is actually quite dark, a very nice shade of olive. Same as the Aero Jacket and the mainline Fatigue pants.