Took a look at the 2020 temperature normals data in Toronto to look at how the weather is changing..
Overall, average daily highs have increased by about 0.5 degrees since 2010. Since 2000, it's been about 0.7 degrees warmer. In 2000, the median daily high was 12.6 degrees vs. 13.3 today.
Overall, you can see a clear trend where temperature growth is most stark in the fall. Summer is increasingly stretching further into September now, which has seen a median daily high temperutare increase by +1.3 degrees in the last 20 years.
Comparatively, the spring weather is warming much slower. May has barely seen any changes, with temperatures increasing by just 0.3 degrees.