We used to see them in the summer all the time up in Timmins, which is 8 hours north of Toronto. Down here in the Toronto area I've seen them in the summer, fall and winter...Sometimes I've read that they might be visible and other times they just appear.
This is a great site with tons of info and data/pictures:
http://www.northern-lights.no/
once you see them you'll never forget it...they are truly magical...