Hello, thank you for your inquiry. You will find that the fit of our Weekender Jacket is quite typical of our mainline offerings. It is designed to be worn over additional layers without being too bulky. You'll notice that is is a bit shorter than our traditional offerings but the chest size remains standard. We would still recommend that you select a medium though, as your arms and shoulders will have remained the same. These factors truly determine the need to size up or down.

We do hope this information is helpful.
Kind regards,
Brooks Brothers