EDITOR’S NOTE: A previous version of this story incorrectly stated that this year was the last palindrome week this century. The story has been updated.
RALEIGH, N.C. (WNCN) — Tuesday begins 10 consecutive days of something kind of rare and pretty cool — palindrome dates!
A palindrome is, as defined by Merriam-Webster, “a word, verse, or sentence…or a number that reads the same backward or forward.”
Tuesday begins a string of 10 consecutive days where the day’s date can be read the same way backward and forward, depending on how you format your dates.
According to TimeAndDate.com, “[b]ecause formats vary from country to country, not all dates that are considered palindromic in one kind of date format are Palindrome Days in another.”
For us here in America, we generally structure our dates in a month-day-year format. If you use the m-dd-yy format, in this case, it allows for a series of 10 straight palindrome days, beginning today. If you use the also-popular mm-dd-yyyy format, we won’t have palindromic days.
The 10 straight palindromic dates are as follows:
TimeAndDate.com, citing Aziz S. Inan, an electrical engineering professor at the University of Portland, says there are 12 palindrome days in the 21st century (Jan. 1, 2001 to Dec. 31, 3000) when using the mm-dd-yyyy format. The first was on Oct. 2, 2001. The last will be Sept. 22, 2290.
If you use the dd-mm-yyyy format, there are 29 palindrome days in the current century, according to Inan. The first was 10 Feb. 2001 (10-02-2001) and the last will be a leap day, 29 Feb. 2092 (29-02-2092).
Palindrome days or weeks are much more common in the m-dd-yy format. In fact, every year since 2011 has had 10 consecutive palindrome days, according to TimeAndDate.com.
If you write your date in the m-dd-yy format, every century has nine years with 10 straight palindrome days. These years are always in the second decade of the century, according to the website. Every year between 2011-2019, 2111-2119, and 2211-2219, will have 10 consecutive palindrome days. The same is true for previous centuries.
Next year (2020) will also have 11 palindrome dates, nine of them consecutive.
2021 will have 22 palindrome dates, 11 in January and the other 11 in December.
2022 will have 10 of them. There will be 11 in 2023 and 2030.
“The month this happens corresponds to the last digit of the year. For example, in 1918, 2018 and 2118, the eighth month of the year, August, will have 10 palindrome days,” according to TimeAndDate.com. “Each of these days will begin on the 11th day of the month and end on the 19th.”