Maybe polish the slab and then put down area rugs? When bad weather comes, roll up the rugs for storage.

This product looks nice. I know nothing about the quality, but they say you can contact them for samples.

Here is a link that might be useful: KONTIKI

Thanks for your replies. I'll check out each idea. I like the look of polished concrete, so that is promising. The deck flooring looks nice but may be more cost prohibitive. Thank you!

Thanks for your replies. I'll check out each idea. I like the look of polished concrete, so that is promising. The deck flooring looks nice but may be more cost prohibitive. Thank you!

Vinyl isn't suited to the large temperature swings. It will expand and contract too much, as well as become pretty brittle at that low temperature. Porcelain tile will be your most durable bet. You can get the ones that look like wood if you want a more "indoor" type look. Polished and stained concrete is a good choice too, but it's one of those "either/or" situations in that if you do the concrete, it's a lot harder to go back and put tile down if you don't like the maintenance of the concrete. And if you do tile, you will find it difficult to remove and smooth the slab out enough for a finished surface later. One or the other. And if you change your mind, you have to rent a concrete grinder to change the surface.

I'd also suggest putting in some underfloor heating cables under the tile to extend the season. It won't make it inhabitable during the coldest months, but it will make your feet warm during the cooler months when you can cuddle with a blanket.