A Palindrome Day happens when the day’s date can be read the same way backwards and forwards. The dates are similar to word palindromes in that they are symmetrical.
Because date formats vary from country to country, not all dates that may be considered palindromic in one kind of date format are Palindrome Days in another. For instance, April 10, 2014 or 4-10-2014 is a palindromic date in the month-day-year (m-dd-yyyy) format, but is not if you write the date as mm-dd-yyyy (04-10-2014); as day-month-year (dd-mm-yyyy: 10-04-2014) or as year-month-day (yyyy-mm-dd: 2014-04-10).
In addition to the format, many people around the world also write the digits on the date differently. For instance, it is common to write only the last two digits of the year – so, 14 instead of 2014. Other such representations include:
- d-m-yyyy or 10-5-2015
- d-m-yy or 10-5-15
- dd-md-yy or 10-05-15
- mm-dd-yy or 05-10-15
Each of these date formats has its own Palindrome Days.Calculate interesting date patterns May 10, 2015 (5-10-2015)
Palindrome dates are rare
Depending on date formats, palindromic dates tend to be rare. Aziz S. Inan, an electrical engineering professor at the University of Portland, Portland, U.S.A. has calculated that in the mm-dd-yyyy format, Palindrome Days tend to occur only in the first few centuries of each millennium (1000 years). The last palindromic date in the second millennium (years 1001 to 2000) in this format was August 31, 1380 or 08-31-1380.
The first Palindrome Day in the current millennium was October 2, 2001 (10-02-2001) and the last will be September 2, 2090 (09-02-2090). In total there will be 12 Palindrome Days in the 21st century if you write your date in the mm-dd-yyyy format.
In the dd-mm-yyyy format, there are 29 Palindrome Days in the current century. The first was 10 February, 2001 (10-02-2001). The last is a special one – it's a leap day! 29 February, 2092 (29-02-2092) will be the last Palindrome Day of the 21st century.
Upcoming Palindrome Daysm-dd-yyyy format
- May 10, 2015 (5-10-2015)
- April 10, 2016 (6-10-2016)
- 5 October 2015 (5-10-2015)
- 6 October 2016 (6-10-2016)