No. I'm an asthmatic and provided I'm not stupid, I'm fine down to about 0F. If I don't dress appropriately, I get quite cold (my hat, gloves and neckwarmer live in my coat pockets, so I *always* have those... I might be missing other critical clothing if I'm being dumb tho). I'm not really acclimated to 0F yet, so I limit my exposure... the other posters aren't kidding when they talk about the dangers of frostbite.

It's important in a lot of cooler climates to drink enough in winter. The air can be quite dry so you get dehydrated quickly.

Most people will find 30F comfortable if they're walking briskly and are dressed reasonably. Hat, jacket, gloves, long pants and boots or insulated shoes. If you're trying to wear winter cycling gear, it might be too light, especially if you are always complaining of the cold. When I bike in cooler weather, I look to be slightly chilly when I start out, but not actively cold. I can always unzip my jacket or take off my hat if I'm too hot. If I'm cold when I start out, the moment I need to walk I'll be freezing... with no way to warm up. Ick.