How to correctly display dates in Russian?

Question

Working with date/time

The generally accepted short form of the date in Russian is 02/21/2012.
What about the long form? Everything is simple in English: February 21, 2012 and nothing else.
As for the Russian language - the question is ...
February 21, 2012
or
February 21, 2012
or
February 21, 2012
Which is correct?
I myself tend to the first option, as the most concise and understandable to everyone, where there is nothing superfluous.
The second option seems too long for me. The third one is embarrassed by this same "g.", which is like a dog's fifth leg.
* If it matters, we are talking about displaying the date on sites, for example, the date of an upcoming event or the date an article was published, when the year of the displayed date does not coincide with the current year.

Answer 1

From the point of view of the norms of the Russian language, all three options are correct. The use of one form or another depends very much on the style of the text. Any of these forms can be used for writing in any modern documents, with the exception of scientific and technical documents, for which the form of writing dates is defined in GOST 7.64-90.

Answer 2

From the point of view of the rules - the first option is just wrong, the 2nd and 3rd are correct.

Answer 3

There is a libicu library , it knows everything and is aware of all the changes, use it.

Answer 4

All three options are correct, from the point of view of the norms of the Russian language.
If you need to display the date on the site, you will agree that it makes sense to add a year only if it does not match the current one. This applies to the rest, well, you probably noticed, now, on most sites they write in this style: "5 minutes ago", "2 hours ago", "3 days ago", "11/25/2012"
There was a lot of controversy about this . In my practice, I will say this: I have not yet seen people who were not satisfied with such a spelling, because in most cases, a person only needs to know "approximately" when the action was performed.