It's National Sibling Day on April 13th.
More on Sibling Day and the other days on the 13th below.
We detected 5,920 references to national Sibling day on 13th the April. There were also a total of 114 other national days mentioned including: Grilled Cheese, Siblings, American Sign Language and Scrabble Day.
The day shown for 'National Sibling Day' is shown as we detected that day mentioned the most out of all the references to national days there were on April the 13th 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!