I got to wear these sooner than I thought when it was in the 40s (F). I had an underlayer as well, although I don't recommend a thin underlayer if there is wind.  I was warm and comfortable, especially after I got settled and had pedaled for a bit.  I would wear a wind jacket if there is a more than 10 mph gust, but otherwise these are great.  I have several of these, thermal and otherwise and have no complaints.  They do the job and do it well. Thanks