Sunday, February 02, 2020
Today's date is a palindrome.
02.02.2020
This doesn't happen very often.
01.02.2010
11.02.2011
21.02.2012
02.02.2020
12.02.2021
22.02.2022
etc
Three times a decade, by the looks of it.
In the 21st century the special month is February, because 20 backwards is 02.
The general format for these eight-digit palindromic dates is
xy.02.20yx
And there are 29 days in February, so there are 29 palindromic dates.
The first was
10.02.2001
and the last will be
29.02.2092
because, fortuitously, 2092 is a leap year.
But that's not all.
Seven-digit palindromic dates are also possible.
1.10.2011
2.10.2012
...
8.10.2018
9.10.2019
There are nine of these this century, all in October, and all in the 2010s.
We've already had all the seven-digit palindromes in the 21st century, there are no more.
In total this century there are 29 red palindromic dates and 9 blue palindromic dates, making 38 in total.
So... at present, palindromic dates aren't that rare.
There's been one every year since 2010, and this will continue until 2022.
But after 2022 the next palindromic date isn't until 2030.
And then we'll only get three a decade for the rest of the century.
Diversion
The 20th century only had 21 palindromic dates, all of them blue, and all in September.
10.9.1901
20.9.1902
30.9.1903
...
19.9.1991
29.9.1992
n.b. Other palindromic dates are technically possible if you're willing to mix leading zeroes
e.g. 08.9.1980
...but I'm not counting those.
The 22nd century will have 31 red palindromes, all in December (e.g. 15.12.2151)
plus 21 blue palindromes in January (e.g. 27.1.2172)
and 9 blue palindromes in November (e.g. 4.11.2114)
making 61 in total.
The 23rd century has no red palindromes, because there is no 22nd month.
but it still has 19 blue palindromes in February (e.g. 13.2.2231)
and 9 blue palindromes in December (e.g. 6.12.2216).
It also boasts 81 six-digit palindromes
(which only happen in years when the first two digits are the same)
1.1.2211
2.1.2212
...
8.9.2298
9.9.2299
...making a grand total of 109.
The 24th century drops back to 22 palindromes, all blue, all in March. (e.g. 18.3.2381).
Of course all this only applies if you format dates like this
day.month.year
It doesn't work in countries like the USA who do this
month.day.year
Diversion 2
Red palindromes in America are very different.
10.02.2001
01.02.2010
...
08.02.2080
09.02.2090
This century there are only 12 eight-digit US palindromes
(always on the second day of the month)
1.10.2011
2.10.2012
3.10.2013
...
8.30.2038
9.30.2039
But there are also 26 seven-digit palindromes
(all on the 10th, 20th or 30th of the month)
Altogether this adds up to 38 US-style palindromic dates this century.
By coincidence, 38 is the same total as for the UK date format.
This isn't usually the case, but in the 21st century it is.
What's really special about today's date is that it's a palindrome in both the UK...
dd.mm.yyyy
02.02.2020
...and the US.
mm.dd.yyyy
02.02.2020
This is extremely rare, indeed it's the only such date this century.
Technically the last time this happened was
11.11.1111
although nobody in the USA was writing dates back then.
The next multi-format palindromic date will be
12.12.2121
which is over 100 years into the future.
And after that it's
03.03.3030
So make the most of today.
02.02.2020
Maybe write a cheque or something, just for the sheer palindromic satisfaction.
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