to me, leather is one of the best wind stops i have ever owned. i have often said "isnt that why god made cows?? hahaha"that being said, there are a couple things to keep in mind. you want gloves that go over the ends of your sleeves, you want a good zip out liner(thinsulate for instance) and absolutely there needs to be a flap over the zipper, some jackets just have the zipper exposed, that dont git it, the flap keeps the air from slippin in through the zipper. also a neck warmer is nice to have and you can get them cheap at just about any bike show vender that has jackets and such. i often will wear a bandana over my mouth and chin, and i have noticed latley there are leather bandana type things available already cut to fit with velcro in the back. so.... the right gloves,jacket,chaps,and under garmets all play a role in staying comfortable. at 20 to 30f you can stay comfy, its when it gets teens and below it becomes a little more difficult, thats when i usually grab a magazine or newspaper to shove up under my jacket hahahahahha. but i havnt had to do that in a very long time( ya see... i live in fla. again hahahahaha)
oh another thought, i have also been known to put my raincoat on over my leather to add protection from the wind after all it is a windbreaker right hahahahahahahahaha
