Using the Environment Canada monthly summaries I have made up 2 gif movies that show which weather stations reported data for each year from 1841.
1974 with 2826 is tops for number of stations. In comparison, 2014 so far only has 1215 stations. There were more stations reporting in 1951 than 2014.
(I don’t know why a weather station in South Dakota shows up in the monthly summaries.)
The 1841 to 1864 part is kind of slow. Toronto is the only station. One gif has Station Names. Not terribly readable. But fun. Click for bigger.