Silk.

I'm sewing something in silk right now (so lovely!) and that reminded me of something I've been meaning to talk about: silk!

I've seen a lot of people in SCA say something like, "Make sure to make your summer garb, or at least chemise, out of silk, because that will keep you cool."

Well... not necessarily. "Cool" is a really relative term in this situation.I got a silk scarf for Christmas, and despite the incredibly thin fabric, the instant I wrapped it around my neck, I could feel it reflecting my body heat back to me. So, in that situation, it was quite warm.

When it comes to silk, it doesn't insulate like wool, or breathe/wick like linen. It reflects heat.

When you see Middle Eastern garb and gape at the amount of layers and length of the garb, wondering how they could ever wear that much clothing in that climate, think about this: The silk is reflecting their body heat back to them, AND (this is the important part) reflecting the environment's heat away from them. So when you're hanging out in a 120 F desert, the 98 F of your body temperature is relatively cool. Likewise, when it drops to 60 F at night, you'll feel pretty warm. (I have a personal account from a friend who was deployed in Iraq that when you're acclimatized to daytime that hot, 60 F literally does feel like freezing.)

So, if you're choosing silk, keep in mind the average temperatures for where you'll be wearing it. Here in Utah, it doesn't much get above 100 F or so in the summer, so wearing silk then won't make much of a difference, and linen is generally cheaper. But wearing a silk chemise would make quite a difference in winter--with wool on top, of course. No way is all-silk garb going to keep you warm enough in Utah winter. Not with the wind and snow.