September 2019 boasts the last Palindrome Week of the decade

Tuesday marks the beginning of a palindrome week.

For 10 consecutive days, the date — written in the m-dd-yy format — will be the same forwards and backwards:

9-10-19

9-11-19

9-12-19

9-13-19

9-14-19

9-15-19

9-16-19

9-17-19

9-18-19

9-19-19

Palindromes are words, phrases or sequences that can be read the same forwards as backwards, and depending on which format one uses, palindromic dates can be rare.

In the mm-dd-yyyy format, for example, the first Palindrome Day in the current millennium (Jan. 1, 2001 to Dec. 31, 3000) was Oct. 2, 2001 (10-02-2001). The last Palindrome Day of the current millennium will be Sept. 22, 2290 (09-22-2290), according to Aziz S. Inan, an electrical engineering professor at the University of Portland.Palindrome weeks — such as the one beginning Tuesday, Sept. 10, this year — are not so rare.

Beginning in 2011, every year has had 10 consecutive Palindrome Days. In 2011, this occurred in January and has bumped one month later in each successive calendar year. The next time a palindrome week will occur in the format m-dd-yy will be in January of 2021, then February of 2022, and so on.

Editor’s note: This article was updated to reflect that this is the final palindrome week of the decade, not the century.