It was surely chilly with only jeans on tonight, 1 degree, on my way back from work. I'll arrange to wear leather pants...but I don't know where I can change and where I can leave leather pants while I'm at work, how I can bring a pair of jeans everyday, etc....too much to think. Maybe it's feasibile to ride only with jeans for 30 min. as low as -5C?
I was in Montreal last winter, I rode till early Dec. After that snow covered the road, but I had a few occasions that I was able to ride in the middle of winter when the roads become completely dry. Riding when -10C wasn't too bad as long as it was short ride. In March, I think I started around the same time as you. I do remember the arrival of spring in Montreal was earlier than normal this year, as it was so warm that I ordered to cut the gas to my fireplace in mid March.