I personally don't find Toronto or Montreal subways unbearable (warm, but not crazy), while my time in the London Underground was absolutely miserable - I'm not sure how locals handle that kind of stifling heat. Actually, there was one time I was in the old Toronto Osgoode (pre-opera house) station with a -30 degree wind blowing through - that was chilly!

Actually, I'm kind of sad that Montreal has so few cars left that play "Fanfare" [0]

[0] https://web.archive.org/web/20090823173621/http://observator...