Board Thread:Show-Related Questions and Answers/@comment-33168501-20170923175425/@comment-25926288-20170930110445

Most answers are fine in theory; however, a time based on official timeline spots and some obvious clues would say....

Season 1 (1x01): October 22, 2011 (because it's Emma's birthday)

Sason 5 (5x05): There are pumpkins...so Fall 2013

Season 5 (5x21): It's obviously close to Christmas based on the building decorations.

Season 6 (6x16): January/Febrary 2014 (because Hamilton is close to debut and Adam said it debuts 18 months earlier in Once)