Bluefield Daily Telegraph, Bluefield, WV


March 31, 2013

Egg hunts in the snow or sun? Complex calendar formula behind Easter date

Girls in frilly, pastel dresses and white patent shoes. Boys in argyle sweater vests and make-you-squirm dress pants. It’s Easter Sunday. A day of sunrise services, egg hunts, peanut butter eggs and jelly beans in a rainbow of colors.

The holiday arrived early this year, preceded by a week of snow, sleet, cold temperatures and all-around nasty weather. Daffodils that had popped from the ground found themselves covered in layers of snowflakes. Parents wondered if traditional egg hunts would be held indoors or out — the final decision resting on today’s weather forecast.

And, many asked, why is Easter falling so early this year? Why does the date for this holiday bounce around between March and April? Christmas, Independence Day, Thanksgiving and other holidays are easy. Even without a calendar for 2013 or 2030, we know when they’re going to roll around.

Many are aware of the common calculation for determining the date of Easter: The first Sunday, after the first full moon, after the vernal equinox — a fancy way of referring to the first day of spring.

Yet this formula is only partially correct.


Our calendar may appear easy enough to understand when flipping through the familiar pages, but there are complex formulas hidden within.

The key to knowing the date of Easter depends on the moon. The holiday falls on the first Sunday following the first ecclesiastical full moon on or after the first day of spring. To understand an ecclesiastical full moon, one has to take a look at the Gregorian calendar currently hanging on walls, resting on desktops and tucked inside daybooks across the world.

The calendar is named for Pope Gregory XIII who, in 1582, revised the Julian calendar previously in use. Our predecessor for day and month tracking was named for the famous Roman who put it in place — Julius Caesar.

Way back in 325 AD, a Roman council decided to keep Easter on a Sunday, make it the same Sunday across the world, and know that date in advance. A noble idea, but one that led to alternate Easter dates today.

The council created tables to formulate the date which, as most things are, were later revised in the following years until the sixth century. When Pope Gregory retooled the calendar in the 16th century he, too, made new tables.

And what does this have to do with Easter falling in March or April and the full moon? All those who have spent hours peering through their home telescopes may now proudly ring in on the Jeopardy buzzer.

Pope Gregory’s Easter tables are based on the ecclesiastical full moon, not the astronomical moon — and the two are not always identical.

Western Christian churches, including Protestant and Roman Catholic, use the Gregorian tables for calculating Easter, while Eastern Orthodox churches use the Julian tables.

Due to this variance in the tables, churches may celebrate Easter on different Sundays.


Imagine if a world leader today made the declaration that Oct. 4 would become Oct. 15. That’s what occurred in 1582 when Pope Gregory made his big announcement. The change in the calendar system was made to put our method of tracking the year closer to the actual length of time it takes for the earth to complete an orbit around the sun.

At the time of the change, there was a 10-day difference between the traditional dates on the calendar and the actual time of the year.

Even though it was opposed by many, the switch was made in Italy, France, Portugal and Spain. Other countries, including Germany and Belgium, followed shortly after. It wasn’t until 1700 that Protestant countries made the change to the Gregorian calendar, and by that time the 10-day difference had evolved into 11.

And, again, the people were not happy.

In Russia, the calendar became even more complicated. The country did not make the change to a more accurate calendar until 1918, when the last day in January was followed by Feb. 14.

Imagine, male readers, going from Jan. 31 straight into Valentine’s Day.


Easter can fall as early as March 22 or as late as April 25. Next year, the holiday will fall on April 20 and, in 2015, it will be a bit earlier in the month on April 5. The following year, 2016, it will again hit in March, falling on the 27th day.

For the next five years after that, 2017 through 2021, it will again come in April, falling on the 16st, 1st, 21st, 12th and 4th respectively.

If you are now thoroughly confused about the dates of Easter, holidays, full moons and more, don’t worry. Calendar companies have our backs, and are marking the important dates in bright red letters.


Fortunately, today’s weather appears to have cooperated with those hoping for a snow-free holiday. Although there is a chance of rain in the forecast, temperatures are expected to hover in the high 50s.

While little ones may need to sport coats and, perhaps, rain boots, it looks like backyard Easter egg hunts may not be out of question.

And, who knows, you just might see a few brave daffodils while enjoying the family fun.

Samantha Perry is editor of the Daily Telegraph. Contact her at Follow her at BDTPerry.

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