Strange light in the sky...

Ever since summer I've noticed a bright light in the sky, at first I thought
it was a star but I could not see any others. I'm located just south of
Toronto Ontario Canada. This light appears towards the northwestern part of
the sky and I can only see it at night and when it's clear...So I'm left
wondering what it is exactly...Star? Satellite? Other? Any information would
be great as I see it just about every night and it's driving me crazy...