+1 to whomever said you should be cool/cold when starting out since the commute warms you up. As for layering, it's different strokes for different folks. If the temp is in the 40's, I can make do w/ a tee and wool sweater/pullover and no jacket. The wind allows the wool to breathe and evaporate the sweat. You can apply that to even colder weather if you have heavier wool layers. The windproof shell comes out if it's really windy or raining.