Great advice here. Sometimes you just have to develop an "experiments" budget. I have Windstopper leg warmers, non-windblocking tights, windblocking tights, breathable and nonbreathable rainpants. Plus three thicknesses of longjohns. Dealing with "I need more than shorts" conditions in Kansas ranging from low-50s to sub-zero, mostly windy ranging from 20 gusty to 40 gusty. I now like really warm (age) over cool or cold. For example, I wouldn't go with PI amphibs in the 30s or 40s, but below, they do a nice job. A very nice job. For sub-ten, I put on longjohns, thin to medium. I haven't gone to -20 windchilll, but I've got the thick longjohs for this exigency/