April 10 is a calendar date that normally falls as the 100th day of the year; in leap years it is the 101st. It belongs to the system of the Gregorian calendar used by most of the world. In a common year there are 265 days remaining after April 10. The date is often noted in year-by-year lists of events, births and observances.

Calendrical position and seasonal context

In the Northern Hemisphere, April 10 sits in mid-spring and is associated with lengthening daylight, increasing temperatures and renewed plant growth; in the Southern Hemisphere it marks mid-autumn. Astrologically, April 10 falls under the sign of Aries. Because religious and lunar calendars move independently of the civil year, movable observances such as Easter occasionally coincide with April 10 in some years.

Notable historical examples

  • Some widely recorded historical events are associated with April 10. For example, the maiden voyage of the ocean liner RMS Titanic departed Southampton on April 10, 1912, an event frequently cited in histories of maritime travel.
  • Popular-culture milestones and political events also appear repeatedly on this date; annual chronologies of modern history commonly list occurrences in many domains—politics, science, arts and exploration—on April 10.

Observances and customs

Various secular, cultural and religious observances are held on April 10 in different places. A notable contemporary observance is Siblings Day, celebrated by many people in the United States and elsewhere as a day to recognize relationships between brothers and sisters. Other commemorations, memorials or local holidays may be assigned to this date around the world.

Use in reference works

Encyclopedias and almanacs commonly include dedicated entries for April 10 listing births, deaths, events and observances by year. Such compilations help readers trace recurring themes tied to the date—scientific anniversaries, cultural milestones or the centennial significance of being the year's 100th day. For further detail on calendrical rules and year-length variations see resources on the Gregorian calendar and leap years.