Rage, rage against the dying of the light.

Might I suggest you make it a very early morning stroll, as in around 7 AM, or else a late evening stroll, after 10 PM? Because Montreal heat in August is generally really horrible, not to mention the high smog levels (not as bad as in Toronto, I'm told, but even though I've lived in Montreal for almost 13 years now, my San-Francisco-raised lungs are still stunned into submission every summer here!).