I have worn Pearl Izumi Amfibs for years in really cold weather and I'm totally satisfied with them. Mine are bib tights without the pads, and I wear them over regular bib shorts. They are comfortable for me in temps down to the teens and up to the 50s. I used to reserve them for rides only in the 30s or lower, but they are fine in warmer temps if you are riding at a moderate or easy pace. On fast paced rides, they might get too warm in temps 40s or higher.

I bike commute year-round, so I have gotten a lot of use out of my Amfibs. They are one of the few items of cycling gear that I would buy again with no hesitation or shopping around for competing products.