I helped my BF with his Global Entry application. The current appointment dates for SFO are now in 3/2017.

Data points:
Applied: 8/26/2016
Conditional approval 9/5/2016
Original interview date: 2/24/2017 in SFO.

I kept checking (frequently) daily and was able to move up his appointment: 1/7/2017 -> 12/27/2016 -> 12/24/2016 -> 9/14/2016!!!