There is wide variation between languages in the number of characters required to abbreviate a month’s name.
This post aims to highlight why the display of dates can become complicated when one starts to look outside of English.
Variation by country
Countries vary in their official date format. Some even have multiple accepted official formats.
This variation is well summarized in the Wikipedia page: Date format by country.
Many countries also have a deep dive into their official date display on Wikipedia, with that page located here.
Element sequence
The sequence of day, month, and year varies by country.
The variation of element sequence even occurs within the same country. For instance, the US Military follows DD-MM-YY notation whereas the rest of the country uses MM-DD-YY. Other countries even allow multiple sequences.
Element content
The content length of each date element also varies by country. Some countries officially record date at YY, others YYYY. Some countries display month in letters, others as numbers. Some include a leading zero for days under 10, others do not.
Variation by Language
Abbreviations of the Names of the Months, by Yale University for an example across languages.
Length of abbreviation
Each language abbreviates their month names differently. Some abbreviations are three characters, other abbreviations four characters. Sometimes this variation is even found within the same language.
For instance, in English, February is Feb. and September is Sept.
It remains unclear to me why February is three letters, and September is four. Why is February not abbreviated Feb?and September Sep? I still don't know.
Quora discussion on Sept vs Sep
Wordreference.com Forum: Abbreviation of "September", "Sep." or "Sept." (2008)
Number of letters to spell a month
In some languages, only two letters are needed to write the complete month name. What does one do if the system then forces that all month names are three characters long?
Abbreviation punctuation
Some languages abbreviate with a period. Others an apostrophe.
Capitalization
Some languages capitalize the first letter; others keep all letters in the month in lower case.
Language direction
Some languages read right to left.
Characters
Some languages write in Cyrillic, or ideograms (such as Arabic, Russian, and Japanese).
Similar abbreviations
Some languages when abbreviating month names, produce identical results when abbreviated to three characters. For instance, in French June (juin) and July (juli) both read jui.
However, there are workarounds, in that when represented with three letters, French displays june as Jun, and july as Jul.
https://forum.wordreference.com/threads/abbreviation-of-september-sep-or-sept.929631/
From the series Building the EHR
Section: Conventions / Date Display