Sage is quite hardy and can survive very cold winters. For years, we had a miracle sage plant in an 8 inch pot that I would leave outdoors by the house all year round. Then a couple of particularly seesawing harsh/mild/harsh winters ago, it succumbed. I replanted sage in the ground and it did not survive the following similar winter. So the next year, I brought one potted sage plant indoors and left two in the ground. The potted sage flourished under lights in the basement and one of the in-ground sage plants survived.
sage by fence (late May2006)
closeup sage (late May2006)
potted sage overwintering (Jan 2006); overwintered sage brought outdoors - it needs to be protected from the sun for about a week or so (Jun 2006)