Overview. April 13 is the 103rd day of the year in common years and the 104th in leap years. It lies in mid-April under the modern Gregorian calendar. In common years there are 262 days remaining after April 13; in leap years the remaining count is one day fewer. The date’s position shifts relative to weekdays and movable feasts, so its cultural associations vary from year to year.
Seasonal and astronomical context. In the Northern Hemisphere April 13 falls in mid-spring, a time of increasing daylight and biological activity. In the Southern Hemisphere it occurs in mid-autumn. Astrologically it usually falls under the sign of Aries (roughly March 21–April 19). Traditional birth symbols for April include the diamond as a birthstone and flowers such as the daisy and sweet pea.
How the date is counted
The numbering of April 13 depends on whether the year is a leap year. Leap years add a day (February 29) which shifts the ordinal number of every date after February. Leap year rules in the Gregorian system are based on a 4/100/400 rule: most years divisible by 4 are leap years, but century years must also be divisible by 400. Historical calendar reforms and regional calendar adoptions have changed the ordinal placement of dates at different times in the past.
Observances and cultural events
Several regional new-year and harvest-related festivals fall around April 13–14. These include the Thai New Year (Songkran), the Sinhala and Tamil new year in Sri Lanka, and Vaisakhi/Baisakhi in parts of South Asia. Because some celebrations follow solar or lunisolar calendars, the exact overlap with April 13 can vary by year and locality.
Notable births and events
- Famous individuals born on April 13 include Thomas Jefferson (1743), an important figure in American history, and writer Samuel Beckett (1906). Musician Al Green was born on this date as well.
- Historical events that occurred on April 13 include the surrender of Fort Sumter in 1861, the day after the start of hostilities that are conventionally marked as the beginning of the American Civil War.
Distinctions and trivia. April 13 can be notable in local or national calendars for holidays, anniversaries, or observances that are fixed to that calendar date. Because of differences between civil, religious and regional calendar systems, the same civil date may carry very different meanings in different cultures. When researching a particular year or country, consult primary or local sources for the precise observance schedule.