The docs say: "Returns the day of the week as a number, from 1..7, with 1 being Monday and 7 being Sunday."

That's what the docs for ->day_of_week say. The docs for ->local_day_of_week say "The day corresponding to 1 will vary based on the locale." I suspect you want to call ->day_of_week instead, which will return 5 for the current date as expected.