Just for the comparison. There are some slight variations from state to state but this is the public school system in NSW:

The Australian school year ties in with the calendar year. The year is broken into 4 terms of approximately 10 weeks, with about 2 weeks break between terms. The school year ends in December, just before Christmas. Summer holidays are at this time - usually about 5 or 6 weeks. This totals about 200 days (minus a few for public holidays. Also the first day of first three terms are teacher development days so no students attend on those days.