Mirror hour, in full
The set is small and fixed. On a 24-hour display the doubled hours run 00:00, 01:01, 02:02 and so on up to 23:23, one per hour. French-language sources, where the practice is strongest, keep these separate from heures inversées, the reversed hours such as 13:31 or 21:12, where the minutes read as the hour backwards. The vocabulary travelled into English mostly through translation, which is why the French names still show up on English pages.
The belief attached to them is that the moment is addressed to you, usually by angels, guides or the universe, with a different reading for each time. Interpretations are generally lifted from angel-number tables, so 11:11 borrows whatever 1111 is said to mean. The 11:11 wish, pausing to set an intention when the clock hits it, is the widest-travelled version and circulated well before the fuller mirror-hour system was written down.
A digital clock holds any given reading for one full minute, and the doubled ones come round on a fixed schedule every day. Noticing them repeatedly says something about when you tend to check the time, and about how well a reading sticks once you have decided it matters. That is the frequency illusion doing its ordinary work rather than anything going wrong.
- Pattern-seeing
- Double hour, Heure miroir
A worked example
There are 24 doubled hours on a 24-hour clock, from 00:00 through to 23:23. Each is displayed for a full minute, so together they occupy 24 of the 1,440 minutes in a day, which is one minute in every sixty. Someone who checks their phone a few times an hour will land on one most days without anything unusual happening.
Sources
The frequency illusion, the sense that a newly noticed thing is suddenly everywhere, was named by the linguist Arnold Zwicky in 2005 and entered the Oxford English Dictionary in March 2019.
Language Log — "Frequency illusion" in the OED
See also
Where it comes up on this site
Mirror hour: frequently asked
A time whose digits double or mirror. The doubled set runs 00:00 to 23:23, one per hour. Reversed hours, where the minutes are the hour backwards, are a separate category in French sources.
Twenty-four doubled ones, one an hour, from 00:00 to 23:23.
Because you are looking for it. Selective attention lifts the reading out of a stream of glances you would otherwise forget, and 11:07 and 11:19 leave no trace at all.