I’ve been biking to work (and wherever else I can bike to) year round, 8 miles each way, for 12 years (in Boston) and here’s what’s worked for me.
In the winter I general ride my mt bike with my standard knobby tires, but when it gets icy I switch to studded (Hakkapeliitta W240). Fenders are key - removable front wheel - ‘permanent’ zip tied in place, rear.
I’m a very ‘warm blooded’ person, so start layer up and take off as I go/warm up. Summer riding I’m a sweaty mess.
For my legs: bike shorts, with front side wind/water proof tights over them. Neoprene boots over my standard shoes when the temp hits 32. Light to mid weight smart wool socks. If it’s raining out I throw on my hiking/snowboarding Patagonia Gore-tex shell pants. They are very durable, have required little up keep and have been bombproof for years. Though when wearing them I need to use those Velcro reflective ankle straps so they don’t get caught in the chain-rings.
Topside, which is what I usually take off as I warm up: (summer) cycling jersey, arm warmers, front side windproof vest and rainproof shell. I generally take off the vest or shell when I warm up, weather dependent. I’m presently using the StormPass shell (made in Seattle) with the E-vent material. Can’t say notice much of a difference between it and the waterproof nylon coated shell I had before. With both I have the pit zips wide open, except on the coldest of days. For gloves I have found that run of the mill REI wind proof fleece gloves work as well as cold weather cycling gloves. On really cold days I switch to my water/wind proof snowboarding gloves.
Overall I don’t really start gearing up until the temp hits the mid 30’s. Until then I’m usually wearing some mix of vest, arm warmers, Mt. bike shorts, full fingered gloves and wool socks.
Until recently I’ve used a med sized courier bag (Bailey bag) to carry work gear. I just switched to a waterproof ‘cycling’ back pack, primarily because after 8 years it was wearing out and because everyone has been going on about better weight distribution. That may be the case but not really liking it. I really like, didn’t realize until now how much I really liked, the way I could swing, back to front, the courier bag, which gave me easier access to keys, badge, bike lock, 6-packs, putting small items in the bag, without having to take the bag off. I’m presently thinking about the various mods to the backpack.
Hope this helped. Safe riding.