The length of the growing season is an important determinant of plant growth and distribution. Longer growing seasons may increase plant productivity and allow for new planting opportunities in agricultural and forestry settings. However, related changes in pest species, fire regimes, droughts, and other climate extremes may limit the extent to which these gains are realized.

There has been a significant increase in growing season length (approximately 2 days/decade) across the country over the 1950–2010 period. If CO2 emissions continue to increase, it is projected that growing seasons at the end of the 21st century will be 20–40 days longer than those currently experienced across much of Canada.