Article 2 (Mar 2021): How the date of Easter is determined

The day you set out Easter baskets is the result of ancient calculations involving the spring equinox, the full moon, and the date of the Jewish Passover.
              
Easter always occurs the Sunday after the first full moon after March 21. It always falls between March 22 and April 25. This year, the first full moon in March 2021 was March 28, which means the next Sunday is April 4, the date of Easter in 2021.
              
What does March 21 have to do with it? That is the date set, for simplicity's sake, by the church in 325 AD as the spring equinox. It isn't actually the same as the astronomical equinox, which can occur on different days.
              
What does Easter have to do with the Passover? Jesus instituted Christian communion at the Jewish ritual meal, the Seder. Celebrated by Jews for more than 3,400 years, the Seder is part of Passover, when Jews celebrate the Biblical account of the Israelites' escape from 400 years of slavery in Egypt. Easter is intended to be set in accord, or even be part of Passover -- called Pesach in Hebrew and Pascha in Greek. Most western languages use a variation of Pascha as the word for Easter, but English is an exception.
              
Because the Jewish lunar calendar and the Christian solar calendar don't coincide, Easter and Passover often occur at about the same time, but rarely on the exact same day. In 2021, Passover began March 27.
              
The date of Easter is currently calculated to the year 2299. It won't be on April 4 again until 2083.