Q&A on the News

Q: I noticed that 7/1/17 reads the same backwards and forward. After 8/18/18 and 9/19/19 when will this happen again? — Lance DeLoach, Thomaston

A: Calendar dates expressed only in terms of the rightmost two digits of the year number are referred to as palindrome dates with two-digit year numbers, Aziz Inan, an engineering professor at the University of Portland (Ore.) who studies palindromes, told Q&A on the News via email.

“Note that unlike the palindrome dates that include all four digits of the year number, the two-digit year palindrome dates completely ignore the leftmost two digits of the year number,” Inan wrote. “For this reason, these palindrome dates repeat every century.”

This year contains 11 such palindrome dates, all occurring in July, Inan wrote. One was 7/1/17. The remaining 10 are consecutive dates, from 7/10/17 through 7/19/17.

In years where the day and first digit of the two-digit year are nonzero (such as 7/1/17), there exists one of those palindrome dates in every year in this century, except years 2020, 2030, 2040, 2050, 2060, 2070, 2080, 2090 and 2100. For example, 5/2/25.

He provided a table to Q&A on the News of palindromes from 2017-2035 that shows two-digit year palindromes dates will occur every year.

For example, in 2020, there are 11 palindromes, all in February. For example: 02/11/20. In 2021, there are 22 palindromes, in January and December. For example: 1/2/21 and 12/22/21.

After 2030, the number of palindromes are fewer per year. In 2032, there is just one palindrome: 2/3/32.