1-10 deg full winter kit
10-15 base, long sleeve top and long sleeve Jersey over that with shorts or tights depending on which end of the scale the temp is at.
15+ shorts, base and short sleeve Jersey.
so what do you wear when it is below zero?
I find i tend to stay quite warm on my road bike as the effort is more constant whereas on mtb always stopping to chat, open gates and chat etc etc.
I am always amazed at how much kit a lot of cycle commuters wear. I can be in shorts and base layer and they are still bimbling about in waterproof trousers and jacket. We get something like 10 wet commutes a year in this London so very little need for the sweaty misery of Altura’s finest.
That said its a free world!