My take on (mostly) Winter riding gear
We do not have the same winter season in North Texas that most do. We do not get (much) snow. We don't have picturesque greeting card scenes. We have cold rain alternating with warm sunny days. Very rarely will we get a cold snap that ices our roads for a few days. Nothing serious .. even though we still stock up on bottled water like it's the end times. This winter has been the warmest I can remember (it has been mid-eighty twice this February). Despite this, many of us hang up the bike until spring. Some pull the trainer or rollers out from under the bed (good job by the way) and keep at it, but for the most part we stay indoors. I get it. There's no white stuff, but it's cold! Last summer I resolved to ride more and do my best to keep riding during the cold months. The key is gear (apparel)! Well of course it is. That's common sense. Your mom is in the back of your mind telling you to dress in layers or take a coat. What I wanted to figure out was which things I needed to buy and when to use them. So, I experimented with some of the gear options available during the last few months ... here is what I've discovered so far:
Wool socks (and CEP/compression) - ANYTIME! I'm using a few pairs of both Bontrager and Fox brand socks. The material may not be as important since I have some nylon/spandex socks that do equally well. Wool socks have been one of my favorite items this winter. I never really gave much thought to warming my feet and they seem to be comfortable when it's been warm out too. What I really noticed were how many of the socks I got have a compression band around the arch. This helps during a long ride and the extra support feels great. Keeping them on after a ride is a habit I haven't learned but they're supposed to help with swelling too. All that said, keeping your feet warm is important and wet feet is a definite no-no.
Full-finger gloves - ANYTIME! For several years I wore short or finger-less gloves, and these are common in cycling. I started wearing these last year and really enjoy having a full glove now. In the not-so-cold months these provide some protection from the wind but most still have breathable mesh material, so have something warmer when it drops below 60; such as...
Wind gloves - 55 or less. I had some of these Louis Garneu somethings given to me since they were too big for the original owner but, after having used them several times, I would have no reservations about buying a second pair. These are a must for colder days outside. The biggest enemy to cycling has always been the wind; it makes riding more difficult, and the cold seem colder! These keep you warm by having a wind-proof outer layer that protects your hands while moving through cold air.
Wind vest - 55-60 or less. I have a Bontrager and a shop kit vest. The wind vest for me was the discovery of the year. Keeping your core warm will make the difference for your being able to brave the cold(er) weather. Vests are lightweight and can be easily stowed in a jersey pocket if you get too warm. Some can be made of denser material that provides extra wind breaking, add reflective features, or additional pockets for nutrition or water (or keys, phones, etc.).
Jacket - 50-45 or colder. Bontrager Apres jacket. Having a jacket will really help on those days where you just can't decide if you should go out or not. Most cycling jackets are made for the wind, and very closely resemble wind-breaker jackets. Some, like my Trek-Segafredo, include a thin thermal inner layer for extra warmth
Arm warmers - 55 or less. Pace. I usually paired these with the wind gloves for the same reason. Keeping the cold air off of bare skin keeps you warmer than just having a thicker shirt. The best part about warmers, like the wind vest, is they are easily pealed off when things get a bit too warm. Best at the start of an early morning ride that stars cold but warms up later on. It might be worth mentioning that I almost never used my arm warmers and my jacket at the same time.
Leg warmers - 50 or less. These are good for those really cold days. Your legs are doing the most work and will warm up plenty as you ride, but having some cover on them will help with comfort. Like arm warmers, these can be pulled or removed and stowed in the middle of a ride as it gets warmer. The only thing better than leg warmers would be...
Tights - 40 or less. Covers your whole lower body and in my opinion does a better job of keeping your legs warm than regular warmers; however, they are not as easily moved/removed as warmers.
Neck gaiter - 55 or any kind of colder. I use a convertable one from Bontrager. The best thing I got ahold of during this goofy experiment! This is the swiss-army knife of headwear! Keep it down around your neck to keep the cold air off. Pull it up over your mouth/nose when it gets colder. Pull it higher above your brow and keep your head down to the ears. There are numerous applications! Added perk of being a fluorescent ninja!
Thermal cap (ears) - 45 or colder. Bontrager Windshell skullcap. I haven't had nearly as many rides where I've needed this .. but when my neck gaiter needs backup, this is it. My experience with keeping my head warm is similar to that of my feet; specifically, I just don't think about it. What I am acutely aware of (and you will be too) is how cold my ears feel in the wind. Just like the hands, having painfully cold ears will drive you crazy and make you stay inside. This helps your ears! You could also use an earband/earmuffs or similar product.
Have not yet tried:
Long sleeve jersey
Toe covers* (did a ride in 33 degree weather just this morning and my feet were painfully cold .. so these and booties are next on my list to try!)
Sub-freezing Temp gear
My general advice: if you can manage the first 20 minutes, you're probably going to be fine!
**TL;DR** - Get a bib! Go outside and ride! Temps over 65 use light wind protection. 50-60 use a little more. 40's probably full upper body cover, legs if you need. 30's or less, add tights and maybe booties. 20's, you probably aren't in Texas anymore but consider base layers under all the other stuff. Less than 20, I'll let you know if it I have the opportunity.
Good luck out there! (stay warm)