31June

31June is a term that refers to the nonexistent date of the 31st day of the month of June within the Gregorian calendar. In the Gregorian calendar, June consistently has only thirty days, so 31June represents an impossible date and is often used to illustrate errors, tongue‑in‑cheek humor, or as a rhetorical device in various forms of media.

The phrase appears occasionally in popular culture, frequently as a comedic reference to a missed deadline or a mistake in scheduling. It has been used in the titles of short stories, songs, and internet memes, where the absurdity of a 31st day in June serves to underscore a point of futility or lightheartedness. In some contexts, "31June" has been employed by amateur writers and comedians to deliberately mislabel a date, thereby creating a humorous or satirical effect.

In a broader sense, 31June can be considered a cultural artifact that exemplifies how everyday conventions, such as calendar systems, can be subverted for comedic or didactic effect. The phenomenon has little formal or academic significance but has gained a modest following within internet subcultures that enjoy playful engagement with timekeeping conventions.