Overview
March 18 is an ordinal date in the Gregorian calendar. In a common year it is the 77th day; in a leap year it is the 78th day. Because of the way leap years are counted, there are 288 days remaining after March 18 whether the year is common or leap. The day sits in the late winter or early spring period in the Northern Hemisphere and late summer or early autumn in the Southern Hemisphere. The mechanics of leap years and year numbering are described in sources on leap years and the Gregorian calendar.
Calendar position and season
March 18 usually falls two or three days before the March equinox (which normally occurs on March 20 or 21). As a result, seasonal perceptions vary: in the north it is often associated with the last days of wintermoving toward spring, while in the southern hemisphere it appears near the transition from summer to autumn. Because of regional climates and cultural calendars, March 18 can mark different stages of agricultural or religious cycles around the world.
History and notable events
Across history a wide variety of political, scientific, cultural and military events have occurred on March 18. One well-known event is the first spacewalk by Russian cosmonaut Alexei Leonov on March 18, 1965, a milestone in human spaceflight. Other years have seen proclamations, battles, legal acts and works of art associated with this date; the specific significance depends on national and local histories.
Observances and cultural significance
Several modern observances are tied to March 18. For example, Global Recycling Day, established in the 21st century to promote recycling and resource recovery worldwide, is observed on this date by many organizations. In addition, religious calendars can place March 18 within Lent or other movable observances, and various countries sometimes schedule national or local commemorations on or near March 18.
Uses, computation and trivia
- Counting: March 18 can be used as a reference point when calculating day-of-year numbers and remaining days in a year.
- Calendar reform: dates before the Gregorian reform (1582) may be recorded as different calendar days in older sources, so historians note whether a date is "Old Style" (Julian) or "New Style" (Gregorian).
- Variation: the weekday for March 18 shifts each year and is used in public calendars, planning and anniversary observances.
Because it lies close to the equinox, March 18 is often a transitional date in seasonal, agricultural and educational cycles and therefore carries practical significance beyond the purely calendrical one.