@Recontra thanks so much for asking! We have reached out to our Co-op Brands designers to see if they have any specifics on the weight of this jacket - we'll reply again when we hear back.
@Recontra turns out this is a harder question to answer than we expected! Because we don't have anyone in our offices right now, we aren't able to weigh the jacket for you. So, our designers' best guess is that the Men's REI Co-op Out In It Jacket weighs ~10-11 ounces in a size MD, so you'd add a few ounces for an XL. And if you were wondering about the women's version, you'd subtract ~2ozs. We apologize we aren't able to be more precise than this and hope this information helps a bit!