¡La Esquina de la Gramática! Rule 28
Presenting dates in Spanish
A date is the time at which an event ocurr, and it is define with three elements: day, month and year. A date can be expressed in three different models:
The first format, first presents the day, then the month and the year: 27 de noviembre de 2010, 27.11.2010. This is a common international use, and the traditional model among hispanics.
The second format, and the most common format used in the United States, first presents the month, then the day and the year: noviembre 27 de 2010, 11.27.2010.
The third format, first presents the year, and then the month and day. This format is the one recommended to be used by ISO (The International Organization for Standardization) 8601, which is a standard way to express a numeric calendar date that eliminates ambiguity: 2010.11.27 (27 de noviembre de 2010).
http://Ortografía de la lengua española