The warmth factor for boots has been a kind of (very belated!) revelation for me, this winter. Normally we don't get very cold weather in the DC metro area, and there used to be only a few days when my feet would get cold. I complained about it a bit but kind of lived with it.
This year, I bought a couple pair of boots. This was partly in response to reading so many posts and pics from YLFers about wonderful boots, and partly because I searched, unsuccessfully, for "snow boot" boots. One of the pair is quite inexpensive, because I didn't expect to wear or like them a whole lot -- but I knew I needed SOMETHING for cold rain and a bit of snow.
Well we've gotten more than our share of snow, and I have worn the black riding boots to death. Along the way I have discovered a) they are pretty useful in snow, without leaking in spite of the low price; and b) the top of my foot being covered can make an enormous difference in how warm I feel.
But I've digressed from Sveta's point (sorry!). I TELL myself that I am going to wear my skirts, and warm dresses. But mostly I don't. But Sveta, I know from experience downhill skiing in years past, how much difference the right choices of layers can make, so now you've set down a challenge, and I WILL wear at least a couple of skirt looks, before we finish with winter weather! I agree that often, more space between my body and clothing, can actually mean I am WARMER than wearing pants and tights.