The success and growth of the grape and wine industries in British Columbia and Ontario are largely due to the production of premium quality wines made from noble Vitis vinifera cultivars such as Chardonnay, Merlot and Pinot noir. This success has spurred efforts to expand the Canadian grape and wine industry to new regions in these and other provinces, but climate is the main constraint on acreage expansion for production of V. vinifera cultivars. Sustainable production of V. vinifera requires sufficient growing-season heat, a long frost free period, and winter temperatures that rarely dip to below bud-lethal (< -22 °C) or vine-lethal (< -25 °C) levels.
Historical weather data can be used to assess climatic suitability for grape growing. Using data from Environment Canada (https://weather.gc.ca/) we produced summaries of the historic climate characteristics for a selection of Canadian V. vinifera growing locations: Osoyoos, Summerland, Abbotsford and Duncan, BC, Vineland, ON, and Kentville, NS. Indices derived from the data include growing degree days (GDD, base 10 °C), consecutive frost free days (FFD), annual minimum temperature, and daily record low temperature for periods spanning the past quarter to half century.