I have two of 5 vehicles on an annual change. I change them the 1st 2 weeks of January every year just so I remember. Things are pretty mild here in the SF Bay area.
I think after the Lakeside stressing scenario (hot Summer) is probably the best time. So, pick Halloween or Thanksgiving week.
2013 Subaru Outback 2.5l, 3k miles, 2nd oil change
Out: M1 0w-20 syn w Subaru oil filter
In: Amsoil 0w-20 SSS, Subaru oil filter (new motor, no after market filters available yet), modified Fumoto valve to ensure full drain.