Now for cooling, the montreal region has subzero temps from lateish november to somthing like almost april...
Apparently Wikipedia has a half decent article.
https://en.wikipedia.org/wiki/Temperature_in_CanadaNot sure about that freeze water in the winter and use it in the summer idea at such a low latitude...
But yes, using an artificial lake (or even a real one... given the population does not go bersek about protecting the wildlife) as a heat echanger might be an idea. Lake would most likely come close to freezing in the winter (need to engineer this properly) but in the summer you could get water from the depths to provide extra cooling power. Idea, put a beach there, get cheers from the population.
Other idea: run a river from up north in your datacenter and you've got a nice cooling strategy for basically... free.
Better idea yet... Build the datacenter on top of the hydroelectric damn... Last thing to do is to run the lines... Not like Quebec had not mastered running lines over hundreds of kilometers anyways, they've been importing power from the north for decades.