Honestly, going strictly month by month is a bit arbitrary. You could pick another month-long stretch from 8/23 to 9/23 (including several games of AAA), for example, where he put up an .860 OPS...
For the most part, he mashed in the second half last year, as evidenced by an overall OPS well north of .900. Except for like a two week stretch in mid August where he was banged up and eventually was forced to sit out a few games.