I think you may be asking for too much. I don't know if you will find a pair of gloves that will perform well at 20F, yet let your hands breath at 50F. I can make a suggestion based on my experience with a product however. I recently purchased a pair of AGU Sirocco Winter gloves. I tested them out today (44F) on a 36 mile ride. The gloves were very comfortable, my hands remained mobile, and the built in palm padding was a plus. I did have a slight perspiration buildup after the ride however. I do not feel these gloves would not be adequate for me if the temps got under 30F for any length of a ride (+1hour). In short, I am happy with them, the price was right, and I feel they may fit the bill for you. Online retailers have them for 20 bucks now. give em a try.
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