Ah, what a difference a week makes! Last Tuesday it was -27C, buut today it's +1C. Most of the snow has melted, but there are still a couple of bad patches to deal with, so the studs stay on. I remembered to pump them up to 40 from 25 psi, and that made the ride in a lot easier. I'll reassess whether to break out the slicks or not after seeing how the ride home is.