The biggest threat to Canada’s V. vinifera premium wine industry is from extreme cold weather events during which temperatures colder than -20˚C can severely damage or kill grape buds and vines. A 2009 survey of winter damage in the Okanagan and Similkameen valleys found that cold injury levels ranged widely for many varieties in response to minimum temperature exposures. We will evaluate the levels and variation in winter hardiness levels in the major grape varieties grown in the Okanagan and Similkameen valleys during the dormant period from leaf-fall to budbreak, and will elucidate factors in vineyard management and site conditions that affect cold hardiness. From these results, vineyard management practices that maximize grapevine cold hardiness will be recommended to industry.