Earliest Easter Date
Usually, Easter Sunday is in April, but this year, 2013, Easter is being celebrated on March 31st, which is quite early. But how early can Easter be?
We don’t have to look back very far to see that celebrating Easter in March is not uncommon — it was also on the 31st in 2002. In 2005, it was even earlier (27th). The earliest 21st Century Easter so far, however, came in 2008, when it occurred on March 23rd.
Actually, celebrating Easter on March 23rd is very unusual, and 2008 was the first time since 1913. It’s not going to happen again until 2160. But is that the earliest it can be?
Calculating Easter Date
Calculating the date of Easter is a little complicated, but it’s related to the vernal equinox on March 21st. The vernal equinox is, roughly speaking, one of the two times each year when day and night are equal. Astronomically, it’s more likely to be on March 20th, but for the purposes of Easter, tradition has it fixed at the 21st.
To work out when Easter is going to be, watch out for the first full moon on or after March 21st. Easter will be the first Sunday after that. So the very earliest Easter can occur is when the full moon appears on Saturday, March 21st. In that case, Easter Sunday is on March 22nd.
As you can imagine, these events don’t coincide very often. The last time was in 1818, and we’ll be waiting until 2285 for the next occurrence!
Incidentally, during the 21st Century, celebrating Easter on March 31st will be quite commonplace, occurring 5 times in total. No other day is more common, although April 15th and 20th occur 5 times too.