If you're buying a Windbar tee for layering—say, over a hoodie or a long-sleeve—you'll want to size up. A boxy fit gives you some extra room, but not always enough for a thick layer underneath. Going one size up ensures the tee doesn't pull across the shoulders or feel tight in the chest.

On the flip side, if you're wearing it solo, your usual size is probably fine. The boxy cut already gives you that relaxed look without needing to size up.