I find dressing in layers to be most effective, especially for upper body. I tend to wear (cargo or golf) shorts for work from late spring to early fall. When over night frost starts, I wear loose fitting wind/rain pants over the shorts in the mornings along with a long sleeve jersey over a T shirt and windbreaker/rain jacket if needed. Full fingered gloves and a fleece "ear-band" under my helmet.

I have a few relaxed fit jeans or khakis that aren't too restrictive, but they can be cold in freezing temps, unless covered with wind/rain pants or insulated snow pants once winter weather starts. At that point a light insulated parka and balaclava or face mask under the helmet along with insulated gloves, mittens or "bar-mitts." Foot wear goes from athletic shoes w/half clips, to low cut hiking boots and finally Thinsulate Kodiak winter boots on platform pedals.

Along this transgression, bike and riding style changes as well. Going from rigid hybrid (700C) to hard-tail (26") to 3 speed (26" studded tires) - each step brings slower speeds, a more upright potion (higher stem/bars), with slightly lowered saddle to allow for the extra bulk of clothing / emergency dismounting.