I know someone who has three or four different thicknesses of pure lambswool jerseys for wearing while he's cycling, at different air temperatures. It never really gets all that cold down south here at 56°N and frankly I think spending ten minutes dicking about over which jumper you're wearing for optimal performance takes a lot of the fun out of it.

That said, I'm a fat 52-year-old, and I cycle in jeans and a T-shirt, and if I start to feel cold it's a sign I'm not pedalling hard enough and I should get the boot down a bit, burn some calories.

I'm still faster than many-jerseys-guy.

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?