Welcome to Montreal!
I think the regular activities start in September, although I’m not on the executive team so I’m not the best informed.
There are however many rides that take place before.
I’m thinking about going on a gentle (~30 km/h) ride to Mont St-Hilaire Saturday morning from Atwater market if you’d like to join. It’s about a 100 km round trip.
Another fun ride is to the Mardis cyclistes de Lachine. The men’s race starts around 7:00 every Tuesday. There are just 2 races left. I go on occasion, as do other members of the team, although no one on the team is racing this year. I’ll probably ride there next Tuesday.
The most popular riding spots in Montreal are the Formula 1 racing track on Jean Drapeau island, and the Mount-Royal. Adithya, our president, has posted a few more good Strava routes on the forum.
There are also group rides up the Mount-Royal organized by a local cycling cafe, although they are ridiculously early.