THE CLIMATE OF WESTERN CANADA 31 



th? spring when plant growth starts and the time in the 

 fall when it stops. Unstead worked this out from the 

 meagre data that were available with the results 

 indicated on the map.! In arriving at these re- 

 sults he arbitrarily took the time in the spring 



Fig. 15. — Temperature Zones of Canada. 



As determined by the accumulated temperatures between time in the 



spring when growth of cereals starts and time in the fall when it 



normally ceases. — After Unstead. 



when the average daily temperature rises above 5''C. 

 or 41 °F. and the time in the fall when it de- 

 scends to 10°C. or 50°F., as being the time when 

 plant growth starts and stops respectively. 



In the report of the same investigation he pointed out 

 that at Ottawa, Red Fife would mature with an ac- 

 cumulated temperature of 1330 degrees, Ladoga with 

 1210 degrees and Early Riga with 1030 degrees. With 

 our longer hours of sunlight here and the very early 

 varieties that are now available the possibility of grow- 



t Reportea in "The Geographical Journal", April and May 1912. 



