Climatic Characteristics of Vitis vinifera Production Regions in Canada

Carl Bogdanoff, Pat Bowen and Brad Estergaard, Summerland Research and Development Centre, AAFC

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 (see attached charts).

GDD and consecutive frost free days were derived as:

- Seasonal (Apr to Oct) GDD = daily ((Tmax - Tmin)/2 - 10), including only values > 0.

- Consecutive FFD = number of consecutive days having Tmin > -1˚C.

The record of annual minimum temperatures shows the frequency of lethally cold winters at each location. Daily record low temperatures, from October 1 to April 30, indicate the potential for low- temperature exposure and damage risk during this damage-prone period. Utility of the data for risk assessment is dependent on the length of the data record and whether climate change trends have been detected. In addition, as a result of cold air drainage and pooling, temperatures can vary spatially in a vineyard by as much as +/- 5˚C. This topography-related temperature variation results in sites warmer or colder than average for a region which emphasizes the importance of site selection to the long term success of a vineyard.

Summerland RDC Wine Grape Research

Annual Growing Degree Days, Consecutive Frost Free Days, and Minimum Temperatures in Six Grape Growing Regions in Canada

Summerland RDC Wine Grape Research Annual Growing Degree Days 2005-2016

Osoyoos, British Columbia Abbotsford, British Columbia

2000 Average GDD = 1571 2000 Average GDD = 1064 1800 1800 1600 1600 1400 1400 1200 1200

1000 1000 GDD 800 GDD 800 600 600 400 400 200 200 0 0

year year

Summerland, British Columbia Duncan, British Columbia

2000 2000 1800 Average GDD = 1348 1800 Average GDD = 986 1600 1600 1400 1400 1200 1200

1000 1000 GDD GDD 800 800 600 600 400 400 200 200 0 0

year year

Vineland, Ontario Kentville, Nova Scotia

2000 2000 1800 Average GDD = 1565 1800 Average GDD = 1093 1600 1600 1400 1400 1200 1200

1000 1000 GDD GDD 800 800 600 600 400 400 200 200 0 0

year year

Summerland RDC Wine Grape Research Consecutive Frost Free Days 1965-2016

Osoyoos, BC Abbotsford, BC

350 350 Average FFD = 186 days > -1˚C Average FFD = 225 days > -1˚C 300 300

250 250

200 200

150 150

100 100 50 50

0

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Consecutive Frost Free Days Free FrostConsecutive 0

Consecutive Frost Free Days Free FrostConsecutive

2010 1965 1970 1975 1980 1985 1990 1995 2000 2005 2015

year year

Summerland, BC Duncan, BC

350 350 Average FFD = 196 days > -1˚C Average FFD = 192 days > -1˚C 300 300

250 250

200 200

150 150

100 100

50 50 Consecutive Frost Free Days Free FrostConsecutive

0 0

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Consecutive Frost Free Days Free Frost Consecutive

year year

Vineland, Ontario Kentville, NS

350 350 Average FFD = 194 days > -1˚C Average FFD = 164 days > -1˚C 300 300

250 250

200 200

150 150

100 100

50 50

0 0

Consecutive Frost Free Days Free FrostConsecutive

1965 1980 2010 1970 1975 1985 1990 1995 2000 2005 2010 2015 1965 1970 1975 1980 1985 1990 1995 2000 2005 2015 Consecutive Frost Free Days Free FrostConsecutive

year year

Summerland RDC Wine Grape Research Annual Minimum Temperatures 1965 - 2016

Osoyoos, British Columbia Abbotsford, British Columbia 0 0

-5 -5 C

C -10 -10

o o -15 -15

-20 -20 Min TempMin Min TempMin -25 -25 y = 0.0475x - 17.865 y = 0.0966x - 13.495 -30 -30

-35

2015-16 1970-71 1975-76 1980-81 1985-86 1990-91 1995-96 2000-01 2005-06 2010-11

-35 1965-66

2005-06 1965-66 1970-71 1975-76 1980-81 1985-86 1990-91 1995-96 2000-01 2010-11 2015-16

Winter Winter

Summerland, British Columbia Duncan, British Columbia 0 0

-5 -5 C

C -10 o o -10

-15 -15

-20 -20 Min TempMin Min TempMin -25 -25 y = 0.064x - 12.358 y = 0.0706x - 19.055 -30 -30

-35

1970-71 1975-76 1980-81 1985-86 1990-91 1995-96 2000-01 2005-06 2010-11 2015-16

-35 1965-66

2015-16 1965-66 1970-71 1975-76 1980-81 1985-86 1990-91 1995-96 2000-01 2005-06 2010-11

Winter Winter

Vineland, Ontario Kentville, Nova Scotia 0 0

-5 -5 Min T

C 10 year avg

o -10 -10 -15 -15 -20 -20

Min TempMin -25 -25 y = 0.0552x - 20.138 oC TempMin -30 -30 y = 0.029x - 22.908

-35 -35

1975-76 1995-96 1965-66 1970-71 1980-81 1985-86 1990-91 2000-01 2005-06 2010-11 2015-16

1965-66 1970-71 1975-76 1980-81 1985-86 1990-91 1995-96 2000-01 2005-06 2010-11 2015-16

Winter Winter

Summerland RDC Wine Grape Research Daily Record Minimum Temperatures

Osoyoos, British Columbia Abbotsford, British Columbia

20 20

10 10

0 0 ˚C

-10 -10

Temp Temp˚C -20 -20 Record Min T 1990 - 2016 Record Min T 1990 - 2016 -30 -30 Record Min T 1966 - 2016 Record Min T 1966 - 2016 2015-16 Min Temp 2015-16 Min Temp -40 -40 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May Date Date

Summerland, British Columbia Duncan, British Columbia

20 20

10 10

0 0

˚C ˚C

-10 -10

Temp Temp -20 -20 Record Min T 1990 - 2016 Record Min T 1990 - 2016 -30 -30 Record Min T 1966 - 2016 Record Min T 1966 - 2016 2015-16 Min Temp 2015-16 Min Temp -40 -40 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May Date Date

Vineland, Ontario Kentville, Nova Scotia

20 20 Record Min T 1990 - 2016 Record Min T 1965 - 2016 10 10 2015-16 Min Temp

0 0

˚C ˚C

-10 -10

Temp Temp -20 -20 Record Min T 1990 - 2016 -30 Record Min T 1966 - 2016 -30 2015-16 Min Temp -40 -40 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May 01-Oct 01-Nov 01-Dec 01-Jan 01-Feb 01-Mar 01-Apr 01-May Date Date

Summerland RDC Wine Grape Research