It’s a natural question to wonder this time of year. The date when Easter falls is calculated by some tricky numerical rules. These come from the desire to make Easter an early-spring (in the Northern hemisphere) holiday, while tying it to the date of Passover, as worked out by people who did not know the exact rules by which the Jewish calendar worked. The result is that some dates are more likely than others to be Easter.
A few years ago I wrote a piece finding how often Easter would be on different dates, in the possible range from the 22nd of March through the 25th of April. And discussed some challenges in the problem. Calendars are full of surprising subtle problems. Easter creates a host of new challenges.
nebusresearch 
And that’s without getting into the system used by the Eastern Orthodox, who don’t observe Easter (Pascha) until May 2 this year.
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Yeah, the Eastern Orthodox system is a separate calculation. In some ways it’s easier since the Julian calendar has a 28-year period neatly compatible with the 532-year Paschal Cycle.
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You really are on top of this!
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Calendars have always been a delight. They seem like they ought to be easy, but then getting them to do everything people want turns out hard.
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