I have never heard of picnic day . Nor do we have many if any picnics in August as it is the wettest month of winter. There are so many days for this and that which have started to pop up but they aren't holidays . Boo to the bright spark that thought of having a picnic in August.
Your memorial day would be the same as our ANZAC day celebrated on the 25th April it is for the Australian New Zealand Army Corp. Here in Cervantes we have a dawn service at 6.30am