Let me preface this by stating my awareness that cold is a relative term. I'm dealing with southern genes here. These are the genes that view anything from 70 to 100 deg F, give or take a little, as optimum riding temperatures with as much or as little humidity as you want to add to the mix. These are the genes that recognize precipitation as a colorless liquid, not something in some demonic solid form that has to be shoveled, chipped, or salted. Also, these genes are old, worn out genes, susceptible to these inhumane temperatures that we've been experiencing of late.
So for this ride, the wind was a mere shadow of itself in the days of yore (yesterday). The temperature was not supposed to break 40 today, but it did by a couple of degrees. Old Sol was resplendent in all of his glory, as he was yesterday.
Until today, I had not attempted to ride in weather this cool. So here is what I tried. Thermasilk long johns, bike shorts, and Louis Garneau Micro tights (wind tights). For the upper torso, I wore a Marmot Infinity midweight base layer, a heavy long sleeve jersey, and the unlined wind jacket. I wore a pair of Wigwam socks. They're some sort of wool blend, I think. I wore my I-look-like-I'm fixin'-to-knock-over-a-7-11 balaclava. I wore a pair of el-cheapo knit work gloves over my regular riding gloves. Temperature range for the ride was 39 to 43 with north winds at 8.1 to 12.7, which were, naturally, headwinds on the inbound leg.
The clothing as described worked out pretty well. I was on the warm side of the comfort range, but this stuff seemed to do a good job of wicking the sweat. I believe I was on the warm end of the range due to the bright sun. My legs felt a little "bound up". I rode without the long johns yesterday, and my legs still felt a little bound up. I'm thinking this combination of stuff should be useful in the 30 to 40 degree range.
I think I'm learning that the wind jacket and wind tights allow all of the other stuff to maintain the warmth they're designed to maintain and get rid of sweat. Without the wind protection, it gets a mite nippy.
I posted this not as some great revelation but just to indicate what worked for me in the conditions stated. For some of us, riding in the "cold" is a challenge, and there are all sorts of clothes one can buy to try to ride in this mess. I've been watching threads in the 50+ forum as well as in the Winter Cycling forum to try to decide what to get. I've added one piece at a time (kinda like the guy who stole the Cadillac) to evaluate the effectiveness of each.
That's my story, and I'm stickin' to it.