It depends on how you define "cold." And also depends on how well you deal in general with cold weather -- some people feel the cold more than others so they need more layers. And everyone seems to have their weak spot that stays cold when the rest of you is comfortable. For example some people struggle with cold feet (that would be me) or cold hands or they start wearing balaclavas to cover their faces as soon as the temperature goes below 55.
Here is one very recent thread that gives good information.
http://forums.teamestrogen.com/showthread.php?t=55882
There are also some good old threads on dressing for winter cycling -- search on "cold" or "winter" to see some.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles