How do you layer your windshirt?

I wear mine (Patagonia Houdini) over my down sweater (also Patagonia) because it offers slight moisture protection and has a hood.

Edit: I do this when not hiking.

I use a Capilene 2 or 3 and my windshirt over that. Never with a down jacket. Windshirts are for moving. Down is for sitting.

You can do it either way. It's easy to throw the down jacket over a windshirt during a break if you are cold. That way you don't have to take the windshirt off. Down jackets are pretty wind resistant.
If you have set up camp for the night then it makes more sense to put the down jacket under the windshirt (if it fits) to hold in a little more insulation and buffer any wind.

Usually if its cold enough to wanna wear down at rest, I'll be wearing a breathable windshirt on the move. To keep things simple, I mostly just add and take away one layer at a time (additive layering), so I'll just layer a puffy over whatever I'm wearing when I stop. Although, if a windshirt or shell is sized properly over a down jacket, it should provide significant extra warmth because of the extra trapped air. If its cold at camp, I'll probably be wearing my windshirt with a puffy over it, and a rain shell over that.

I also prefer sizing a windshirt so it fits closely over a baselayer, to cut through the wind better. And I'll size my rain shell for extra coverage, and to fit over my puffy.

my 2cents, but its hard to go wrong here.

I agree with Jeff. Usually a baselayer (Capilene) and then my windshirt over that when on the move. When not moving, I'll put on an insulating layer if needed.

i try and have things go on-and-off in the same order, all the time. for me it's base layer (something synthetic, white/light color and moisture wicking), power stretch 1/2 zip hoodie followed by a wild things (epic) wind shirt. over that goes either synthetic or down insulation. i seldom bring a hard shell on short duration (less than 3 or 4 day) trips.

I am assuming that since Catherine's question is specific to layering windshirt and down puffy that she is asking about in camp, on occasions when she feels cold enough to wear both. Rather than a general layering question, on-the-move vs. at-rest, etc.

If in camp and wearing both windshirt and down puffy I wear the windshirt as the outer layer. The down puffy insulates by having a multitude of tiny air layers that are stilled, such that your body heat doesn't escape very easily. Wind can stir and displace those layers inside your puffy, and so I find that the windshirt on the outside allows the puffy to do what it is designed to do best on the inside, by the windshirt cutting the wind from affecting the air layers in the down.

Serge said:
"Usually if its cold enough to wanna wear down at rest, I'll be wearing a breathable windshirt on the move. To keep things simple, I mostly just add and take away one layer at a time (additive layering), so I'll just layer a puffy over whatever I'm wearing when I stop. Although, if a windshirt or shell is sized properly over a down jacket, it should provide significant extra warmth because of the extra trapped air. If its cold at camp, I'll probably be wearing my windshirt with a puffy over it, and a rain shell over that.

I also prefer sizing a windshirt so it fits closely over a baselayer, to cut through the wind better. And I'll size my rain shell for extra coverage, and to fit over my puffy. "
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Exactly this..

I'm with J R here.

I wear mine over.

I used to want a loose fitting wind shirt to put over my down. Then I learned, the hard way, that body moisture will kill your down. I did that by climbing to the top of a mountain and throwing on a down jacket. The sweat off my back rendered the jacket useless very quickly.

Now I use the wind-shirt under the puffy as a permeable vapor-barrier to protects my insulation layer. It's a bit of a compromise, the wind shirt still allows moisture through but no so much that it damages the down. However it is still possible for moisture to build up beneath it. Untucking my shirt and opening the collar a bit helps air flow through and take body moisture with it.

Snug wind-shirts wick moisture better than loose fitting ones too.

Edited to add: In camp, where you aren't producing a lot of sweat, then it probably doesn't matter much what order you put them on.

For me personally, also windshirt under down. It's more convenient to add a puffy on top of the windshirt I'm probably already wearing then to take the windshirt off, put the puffy on and add the windshirt again. And that also would mean I'm loosing a tiny amount of heat if I need to take the windshirt off.

The same reasoning for my rainlayer as there is more chance that I'm already wearing it.

So both of them are fitted.