Calling Winter Commuters:

[CorsairMac]

lined tights. A second pair of short would be kind of useless, your legs would still freeze.

It wasn't my legs that was the problem (lined leg warmers).........

[Dianyla]

Here's the range of bottoms that I'll progress through as temperature decreases:

shorts
knickers
shorts + unlined PI thermafleece tights
shorts + unlined PI amfib tights
shorts + tights + rainpants (even if not raining)

I actually don't own any tights with chamois pads. I've tried, but never managed to find some that I like. There aren't very many makes/model of tights on the market every season, so it gets even harder to find a good tight+chamois combination. It's hard enough to find a compatible pair of shorts with a chamois that I love, and there are tons of shorts on the market at any given time.

Also, I use my thermafleece tights quite often in winter for non-bike activities such as skiing/hiking/camping etc, that's another reason to have unlined tights.

[nuthatch]

Ugg, the dreaded winter season booty chill. Corsair, girl, what you need is some sort of spoiler attached to your jersey pockets on the back! Just channel that cold air right on by!

Barring that, if it's cool enough for a jacket, maybe you could find one with an extra long tail. That's what I've wished for on the fall commute, especially a softshell with a long tail and maybe pit zips. I'm not sure why softshells don't come with pit zips - maybe it would make them look too weird.

But that backside does get so chilly even while the front is a sweaty mess!

[newfsmith]

My sequence is pretty much like Dianyla's, knickers usually take me through the 40's if it is dry. Being rather blubber covered, I don't usually have problems with a cold tush until it is in the teens. I do like the Performance triflex tights for very cold weather, they have a wind & water resistent seat panel.

[KnottedYet]

Wool Ibex knickers.

Knickers plus rainpants.

[Kitsune06]

I've never had to commute more than 3-4 miles. That said, I tend to wear lycra shorts, boys' silk thermals (more crotch room for the chamois...) and rain pants. Then scurry to the bathroom to take all that off and put on your regular pants. *shrug* I'll never win fashion awards, but it seems to work.

I rarely have problems getting cold, though. On cold days, I steam after hardly any activity. DGF says it's creepy.

[Geonz]

Heavens, my backside has always had enough insulation. Sweats will work 'til the 40's. THen tights under the sweats. Then tights and thermal undies and sweats. Then the really, really warm tights, the silk undies, and the thick sweats. That works for 4 degrees (F) and 8 miles, and I haven't had to do more than that.

I'm unchamoised in the winter.