My record was -63f/-53c. But it isnt all that bad. There is literally no weather/wind below about -40. No snow. No wind. No clouds. Only strange stuff like ice crystals falling from a clear sku, and snow that squeeks like walking on styrofoam. -35 and windy always felt colder than -50.

Ice crystals: https://youtu.be/4yBNmoa4htE

Does it take 10 minutes to choose? Back when I was commuting, I had different kit depending on the temperature, and it wasn't exactly hard.

>50F: Summer gear, and not much of it. I run hot, and there's no need to make it worse.

>20F: Add a thick sweatshirt and gloves

>0F: Add wool socks, long pants and a wool underlayer, a windproof outer shell, glasses, a hat, a thicker windproof layer over my gloves, and sometimes a scarf depending on how short I'd cut my beard.

>-20F: Similar, but with some extra layers over my core, and the scarf is mandatory.

>-40: Similar, more layers.

<-40: I know my limits. I've nearly gotten in serious trouble before when it's too cold out and I didn't plan for extra wind and a cold pocket near the river or having to walk because of a poorly maintained road or whatever. My gear wasn't especially high-tech, and I just called work and emailed my professors to let them know I wasn't going to make it.

Wind would have me reaching for wind breaking and insulation at higher temperatures.

It wasn't a 10-minute process by any means though. I'd pull out my phone in the wee hours of morning, see that it was X temperature on the homescreen, and plan accordingly. If he's just selecting between a few jerseys that should be even easier, right?

If you start doing longer rides you learn there are general temperature ranges and kit that's fine to commute in or ride an hour in traffic with a rucksack is very different from the kit you want on a 6 hour ride in the countryside. I generally have kit for 0-10, 10-15, 15-22, 22+°C. My 0-10 jersey will boil me alive after an hour cycling in 13°C but likewise my 10-15°C will risk hypothermia in 8°C. There's only so much layering you can do with cycling kit before it starts becoming restrictive.

I'm curious: I do cycle in jeans and a t-shirt while in the city. Up to 45 minutes I'm perfectly fine, but if I'm on the saddle for over one hour I really start to miss the chamois. What's your experience with that?