It's that time again! Or is it??

I'm one of the people who is all like, "Oh, my gosh.  It's August and Costco has their Halloween candy, their Fall wreaths, and their snowmen out.  What idiots." 

Then here's me at home:

While outside it's this:

So, it begs the question - what determines Decorating Time?  If I went by the weather, and for some reason I feel like I should, I wouldn't decorate for Fall until late October.  But that's too late for me.  Should we use the calendar?  Is it just a feeling?  Is it the fact that by 7:30pm it's pretty much dark as opposed to the 9:00pm sunset we're used to all summer?  Whatever it is, it struck me yesterday and I've decorated for Fall.  Now, if the weather would just cooperate I would feel as if it's really ok.