It's National Championship Day on December 17th.
More on Championship Day and the other days on the 17th below.
We detected 669 references to national Championship day on 17th the December. There were also a total of 33 other national days mentioned including: Ugly Christmas Sweater, Maple Syrup, Sally and Bhutan Day.
The day shown for 'National Championship Day' is shown as we detected that day mentioned the most out of all the references to national days there were on December 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!