Father's Day is observed on the first Sunday of September every year, shaping retail trade for the week either side of it. 16 September 2028 falls inside the same 30-day month as this observance, in the first month of the Australian spring, as warmer weather returns across the southern half of the country.
A public holiday that falls on a Saturday sits inside the weekend rather than beside it, so it does not automatically create a substitute day off during the working week; whether one applies depends on the specific holiday and the state. Saturday 16 September 2028 falls on this day of the week, inside the weekend itself.
2028 has 366 days on the calendar. Leap years add a single extra day to February, giving those years 366 days instead of 365 and shifting the day-of-year number for every date from March onward by one compared with an ordinary year. This is the only irregularity in the length of the Australian calendar year.