I'd hate to be a mechanic working outdoors in winter Toronto. Just thinking of handling steel tools with un-gloved hands (otherwise you can't grasp much) makes me feel sorry for those folks.
Nearly all the mechanics I see working now in the UK have gloves, tight fitting "latex" ones. I suspect it's in part to do with evidence suggesting used engine oil is strong carcinogen, and also because most garages have open fronts here. There are plenty of other fluids knocking around you don't really want to be in contact with a lot; also even light latex gloves will stop some scuffs and nicks. I've used them myself occasionally, when it's very cold (just above 0degC/freezing) they help a lot.
Gloves seem more common the more expensive the service is too, so it might be a company mandated 'health and safety' protection.
We try to maximize the number of bookings inside a garage, and they're all equipped with both heated jackets and portable heaters.
When it gets way too cold, we prioritize mechanic happiness and reschedule all the jobs for the day.
Metal gets brittle when it is cold. This will lead to tool breakage (health risk) and bolts snapping rather than turning. You really should not work on a car at temperatures < 5C and preferably you should work in a heated garage. Below -10C it qualifies as torture, not work.
Being a car mechanic is hard enough on the body when working in the best possible setting.