The AAFC map above shows accumulated growing degree days (GDDs) as of May 19. Click here to create your own AAFC weather maps.
GDDs are calculated by averaging daily maximum and daily minimum temperatures for each day, and subtracting the assumed minimum temperature (in this case Base 0) required for growth to proceed. A day with a high of 20°C and a low of 10°C would contribute 15 GDDs on a Base 0 scale.
Accumulated GDDs to date (as shown on the map) would not count toward canola seeded today. Napus seeded today would need roughly another 1,500 GDDs to reach maturity.