Standard Date Format for Genealogy Dates
The most readable and reliable format for presenting dates is two-digit day, followed by a three character abbreviation for the month, followed by a four digit year (dd mmm yyyy). This date style is least likely to create confusion when entering, matching, or merging data and is also called the standard date format (SDF). Each sub-element is separated by a space. The three character month will be in the native language of the researcher. Examples: 14 Jan 2015 (English); 09 Ene 1850 (Spanish). It is especially important that you use this SDF date style format if you have an online family tree at Ancestry.com.
Foreign language three letter abbreviations of months of the year
English - Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
French - Jan Fev Mar Avr Mai Jun Jul Aoû Sep Oct Nov Déc
German - Jan Feb Mär Apr Mai Jun Jul Aug Sep Okt Nov Dez
Hebrew - Tis* Hes Kis Tev Shv Ad1/Ad2 Nis Iya Siv Tam Av Elu
Italian - Gen Feb Mar Apr Mag Giu Lug Ago Set Ott Nov Dic
Portuguese - Jan Fev Mar Abr Mai Jun Jul Ago Set Out Nov Dez
Spanish - Ene Feb Mar Abr May Jun Jul Ago Sep Oct Nov Dic
* The first month of the Hebrew calendar, Tishri, coincides with the secular
months of September/October.