#TIL in Canada it was bears that were historically the predictors of an early or late spring; in US it was groundhogs (or ground squirrels). (Likely) Ameriican newspapers pushing their "biased groundhog agenda" across the border in the early 1900's and a lack of a strong understanding of where the bear-thing came from (first nations? the french? no one really knew) prevented a patriotic pushback. Perhaps the first occurance of the US cultural tidal wave the continues to sweep over Canada?
Articles like "Grading the groundhogs" are only possible with clean datasets: https://www.noaa.gov/heritage/stories/grading-groundhogs