Most of the time, yes. But in summertime it's common in this part of the continent to have thunderstorms that develop late in the afternoon. That might account for the 30-60 minutes lateness you're seeing over the last week or so.

So you're probably fine. And, as noted above, even if you do get a thunderstorm day or some other problem, there are plenty of flights YYZ-YUL. Even if you do miss the connection to your scheduled flight, you shouldn't have much trouble getting one soon afterwards. Good luck!