Gonna be different based on a variety of factors, but with a fleece, hat, baselayers and perhaps puffy pants, I’d say about 25F/-3C +/-.

Montbell.makes good stuff and I don’t think you will be disappointed.

Ha I see. Thanks for the review. Was looking at this or the Permafrost, but trying to get past Gore materials, and can always just wear a hardshell over this anyway. This is a bit warmer too.

Mine is a few years old so.beyond “green” I forget tbh. 🙂

https://ultralightoutdoorgear.co.uk/alpine-light-down-parka/

Weights there.

Hi Josh, I find that a non-mountaineering type shell such as the Storm Cruiser tends to pair best with a similar-sized light fleece or light puffy. However, for a winter weight heavier puffy, sizing up seems to work best. e.g. an XL puffy pairs best with an XXL shell.

I have a dedicated winter shell I wear with my winter puffies. An older version of the Free Rein Parka by Red Ledge that is sized up to go over my the winter puffies. I only wear it in camp . Might work for you if that is what you intend to use the shell for. Sub-$80, too.
https://www.amazon.com/Red-Ledge-Mens-Free-Parka/dp/B00NGB3MGO

Hope that helps!

There has been pro-Montbell hype for at least 15 years that I can recall, and for good reason. Slightly less now maybe as they have increased pricing gradually but consistently over the last four years or so. I wear a large or extra large and with these ultralight materials the weights I have received have never been much over an ounce (usually 1/2 to 3/4 ounce over the medium listing, depending on the item). Most items are only slightly more of a trim cut (in a good, functional way) than typical US sizing, so if you pay attention to their good information on the product pages and unless it specifies an Asian fit, then it’s probably going to fit just fine. I don’t think it’s any different with any other item you order and receive by mail from any other company. I don’t shop and buy as much as I did but I think Montbell may still win for value-per-ounce on many items, and they do offer a number of items that have some appreciably unique features or materials, and nearly everything has a pretty smart design element to it. They have stellar customer service, too, but they will never (thankfully) be a WalMart or an REI/Backcountry. A nice blend are the wonderful people at Enwild (fka Backcountry Edge) although they don’t cater as much to ultralight.