When will you/do you change out all season to winter tires?

I live in the high desert and the nights have been consistently in the high 30°s at night and mid-50°s in the day. I didn’t change out my all season tires last year and didn’t have any issues. This year I’m a little more cautious as I’m working earlier hours and the snow plow tends to clear out our street (on a hill) last. So, what do you do and how are your winters?