Why does stat show different timezones corresponding to different files?

I always thought that the timezone is not stored by the filesystem, and that stat would show times formatted with the current timezone of the user, and therefore if I do stat on various files *today* then the timezone should not change. However this answer https://unix.stackexchange.com/questions/119323/stat-command-detail-information suggests the opposite! Different files appear with different timezones! Does anyone know why?