“The phrase ‘it’s not opposite day’ is always true”

On “Opposite Day,” people say the reverse of what is true. “5th grade revelation: ‘It’s not opposite day’ is always true” was posted on Twitter on July 22, 2011. If it’s not Opposite Day, then the statement “it’s not opposite day” is true. If it is Opposite Day, then the “it’s not opposite day” is false, but it would be the correct answer because its opposite would be true.
   
“The phrase ‘it’s not opposite day’ is always true” was posted on Reddit—Shower Thoughts on January 25, 2016.
   
         
Wikipedia: Opposite Day
Opposite day is a game usually observed by children. It starts by declaration and rarely lasts an entire day. The game involves, that players assume, that statements mean the opposite of what they usually mean. Every action is modified, so that meaning is negated.
 
Sometimes, opposite day is declared retroactively to indicate, that what was just asserted had the opposite meaning of what was originally intended (similar to the practice of crossed fingers to automatically nullify promises). However, the declaration, that it is opposite day, is negated as well, implying that it is not opposite day.
   
Google Groups: rec.sport.pro-wrestling
Today is Opposite Day! 😊
O-Ren
12/21/05
Today is not Opposite Day. :(
 
Twitter
Brian McGreer‏
@BrianMcGreer
5th grade revelation: “It’s not opposite day” is always true.
8:22 AM - 22 Jul 2011
   
Twitter 
Jordan‏
@ApologizeLater
The phrase, “It’s not opposite day.” Is always true. #weedtweet
11:01 AM - 6 Aug 2011
 
Twitter
KC Lemson‏
@kclemson
My six year old pointed out to me that the phrase “Today is *not* opposite day” is ALWAYS correct.
4:43 PM - 7 Oct 2012
   
Twitter
Clay Boneham‏
@CBoneham555
#RandomFactOfTheDay No matter what day it is, the phrase “It’s not Opposite Day” is always true
3:06 PM - 6 Mar 2014
 
Reddit—Shower Thoughts
The phrase “it’s not opposite day” is always true
submitted January 25, 2016 by 1burst12
     
Reddit—Shower Thoughts
The phrase “It is not opposite day” is always correct, even on opposite day.
submitted May 10, 2016 by [deleted]
 
Reddit—Shower Thoughts
“It’s not opposite day” is always a true statement.
submitted October 13, 2017 by PM_ME_BOOBS_N_ASS