It's National Opposite Day on September 17th.
More on Opposite Day and the other days on the 17th below.
We detected 2,560 references to national Opposite day on 17th the September. There were also a total of 80 other national days mentioned including: First Love, Prisoners Of War Remembrance, Opposite and Public Lands Day.
The day shown for 'National Opposite Day' is shown as we detected that day mentioned the most out of all the references to national days there were on September the 17th across social media. Our algorithms examine all of the references to National Days across social media and updates whatnationaldayisit.com hourly, with our homepage displaying the current national day. This crowdsourcing of data method to assess the National Day date is used as opposed to being connected with any Government sacntioned lists :D Hurrah for democracy by concensus!