^^I will second what Dean2 said about the red plaid jac-shirt.
I have the merino wool jacket. IMO it is a Spring-Fall jacket, it is not wind resistant. When moving, it is reasonably comfortable to -5C on a calm day. Layered with the plaid jac-shirt, it is an effective combination to -10C on a calm day. However, I wouldn't be sitting still for any extended length of time at that temperature. Obviously, people have different temperature tolerances, YMMV
It would be improved with the addition of a 2-way zipper and an interior pocket.
In hindsight, I should have bought the 24oz wool jacket, or ordered the Filson 26oz plaid Mackinaw
