(Denny Crane: "Sometimes you can only look for answers from God and failing that... and Fox News".)
British Columbia also has fixed election dates.
I think the fixed date should be nationally set and used for all levels of government; my preferred date would be the 2nd Monday in May (to allow for a fresh fall session) or the 3rd Monday in November (to allow a fall of campaigning before returning in January, and to keep it off the US election week and Remembrance Day)