2012 Climate Data

In 2011 ALGGS volunteers began installing temperature data loggers throughout the Arrow Lakes valley.  This was the first step in our grape vine research - determining if our temperature can support wine grape production.  We wanted a unit that was simple to set up, relatively inexpensive, fairly accurate and with a 3 to 5 year battery life.  After a bit of research we settled on the HOBO Pro2 units, as they seemed to have a proven track record in similar projects. This study will run for 3 to 5 years which should give us enough of a data profile to make a conclusion with.

We installed nearly 40 units in the valley throughout 2011, so 2012 marked the first year of full data we can look at.  Our growing season is calculated from April 1 to October 31 and the specific data we are concerned about is "frost free days" (FFD) and "growing degree days" (GDD).

GDD is a measure of heat accumulation used to predict plant  development rates such as the date that a crop will reach maturity.  GDD is calculated by taking the average of the daily maximum and minimum temperatures minus a base temperature, (in our case 10 °C).  Unfortunately the downside of the HOBO Pro2, is that it over inflates the GDD number and thus we had to calculate it all by hand - ugh.  Thanks Mary Ellen Harris for all the work she did to calculate this for us!

FFD are exactly that - number of days from the last spring frost to the first fall frost.

We broke our data into four regional sections: Nakusp, Arrow Park (east and west), Burton, Fauquier/Needles and calculated an average for each region:

                                   GDD             FFD
Nakusp                        976               146
Arrow Park                  973              144
Burton                         1060             144
Fauquier/Needles        1145             143

Valley Average          1039              144

What do the numbers mean? By comparison:

Summerland               1333             *190
Osoyoos                     1545             *195

* No data for 2012 yet, but an average over the past few years.

We are not the Okanagan, but we knew that,  And we are not going to try and grow the same grapes as they do either. Most of the varieties we have selected will need about  900 to 1000 GDD to reach maturity and need around 130-135 FFD.  2012 was a very cool spring, so we expect the numbers to increase a bit over the years, but overall positive numbers for the varieties we selected for our research plot.