From CBC:

The province re-elected Brad Wall’s Saskatchewan Party government with a large majority on Nov. 7 of this year, which means its next election is scheduled for Nov. 2, 2015.¬†However, federal legislation calls for national elections to happen the third week in October, four years after the previous election. Because Harper’s Conservative government was elected with a majority on May 2, 2011, that sets the next federal election for Oct. 19, 2015.

Then there’s this:

Four other provinces and the Northwest Territories are in a similar situation as Saskatchewan, with their elections set for October 2015.

Prime Minister Stephen Harper’s election date conflicts with ¬†a lot of other provinces’ dates. Clearly, the PM needs a new date for the next election. A late date will keep his party going longer so he’ll probably pick just such a date.