Bonneville Landspeed Racing - Let's Try a Thing.

My garage is attached to the house and generally stays between 5 and 10 C (40-50 F). I find I can work pretty comfortably out there with a jacket on.
My last house had a shop with a furnace. I found I liked having the thermostat set at 50 all winter. Perfect for working with a heavy shirt, no jacket or gloves.