First of all, I ride all winter, however I don't ride when it has frozen the night before on the hilltops and the temperature is still below 40°. I will ride down to about 35° and steady rain or even in the snow, as long as it is not sticking. I don't ride on ice, hence no studded tires, etc. I run fenders and long mudflaps all winter. Michelin PRO4 Endurance in 25mm are the best winter tires I've tried, and I've tried a lot of tires. I use thick wool cycling socks in the winter. They're a little hard to find.
I don't wear waterproof anything, except for the Gore gloves and Lake MTB boots when it's really bad. I find it much better to wear breathable stuff and just layer up enough to stay warm.
[Progression; your exact temperature range for each option will be your own:
1) Plain SS jersey, naked knees, short finger gloves, Sidi Dominator shoes - summer, right? From there:
2) Add wind vest and arm warmers
3) Add short sleeve Craft underlayer and substitute Pearl Izumi Elite Softshell glove for short fingers
From here, always bring a wind vest and Voler Jet jacket in Hi Viz on every ride, bring the PI Elite gloves along even when starting with warmer gloves.
4) Substitute Voler Jet jacket in Hi Viz for vest and add leg warmers, substitute Performance Zonda or PI P.R.O. Softshell gloves
5) Substitute long sleeve Craft underlayer for short sleeve, add arm warmers (this is a versatile combo)
6) Substitute long sleeve jersey for short sleeve jersey-and-arm-warmers combo
7) Substitute Pearl Izumi (PI) Elite Thermal tights with pad for shorts and leg warmers. Add Sugoi Resistor booties if dry or showery. Substitute Lake MXZ303 shoes for the Dominators if wet.
8) When it's really cold and wet, substitute heavy winter jersey or add a second long long sleeve jersey, substitute PI Elite Amfib tights w/o pad and shorts for the padded thermal tights, add dry suit ankle seals over the tops of the Lake shoes (very important), substitute Gore Bike Wear XENON GORE-TEX Gloves or Giro 100 Proof Gloves (even warmer).
Stay home. It is now 34° and raining.