The core component of the search query is the proper noun phrase "Saint Patrick's Day." The term functions as the subject of an interrogative clause that seeks to identify a temporal attribute. The answer to this query is a specific date, which itself is a noun. The observance occurs annually on March 17.
This date was chosen to commemorate the death of Saint Patrick, the foremost patron saint of Ireland, which is traditionally accepted as having occurred in the year 461 AD. It is both a cultural and a religious holiday. In the liturgical calendar of the Catholic Church, when March 17 falls during Holy Week, the observance may be moved to a different date, though secular celebrations typically remain on the 17th. It is a public holiday in the Republic of Ireland, Northern Ireland, the Canadian province of Newfoundland and Labrador, and the British Overseas Territory of Montserrat.
As March 17 is a fixed date, the day of the week on which the holiday falls changes each year. This has practical implications for public celebrations, such as parades and festivals. In many cities, particularly outside of Ireland, major celebratory events are often scheduled for the weekend closest to March 17 to facilitate larger attendance and participation, even if the official date falls on a weekday.
