The Case for Either Date
There is a book I have called Witness to Mystery: Investigations into Christ's Relics. The authors are two Polish journalists who researched much about what scientists and other experts in various fields have found out about many different relics associated with Christ. There is a particular chapter in there about the Shroud of Turin with much to say about the date of Christ's crucifixion. To start, historians place the governorship of Pontius Pilate from 26 to 36. The year would have to be one from that range. The day of the week of Christ's crucifixion has always been considered to be Friday. As for when the first night of Passover began that week, there is some debate over whether it was Thursday night or Friday night. My opinion is that Passover began on a Friday night based on scriptural evidence. For one thing, the chief priests made sure to arrest Jesus before the Passover began (Matthew 26:5 and Mark 14:2). This wouldn't have made sense if Passover began on Thursday night. Likewise, Christ told His disciples he desired to eat the Passover before He suffered, which makes it sound like He otherwise would have waited until Friday night (Luke 22:15). Also, if the Passover began on Thursday night, the chief priests would have already begun eating their Passover meal and would not keep their distance from Pilate on Friday morning so that they could eat the Passover on Friday night and avoid ritual defilement (John 18:28). Scripture also mentions that the Passover was a "solemn" or major one, since its first night also began the Sabbath, which began on a Friday night and lasted through Saturday (John 19:31).
If Christ was crucified on a Friday, and Passover began that night, then we can take a look at the times when Passover began on a Friday night between 26 and 36. The authors of the book did that, and found two dates: April 7, 30, and April 3, 33. Since Christians have always held Sunday to be the day of the week when Christ resurrected, then we can add two days from that and have the Resurrection be on April 9, 30 or April 5, 33.
The Case for April 9, 30
Tradition has it that Christ began His ministry when He was 30 and died when He was 33. Therefore, the credibility of either date I mentioned basically comes down to looking at the possible birth year of Christ. If you follow the many historians who figure that Herod the "Great" died in 4 BC and who therefore place the birth of Christ sometime in that year, then it's very possible that Jesus would have been 33 in 30 (remember, there is no year 0). But there is a detail that St. Peter references from the prophet Joel about Jesus that seems to give credence to the other date for the Resurrection: April 5, 33.
The Case for April 5, 33
Before I get into what St. Peter quoted from the prophet Joel, there's the debate around the birth year of Christ again. While some historians consider 4 BC to be the year of Christ's birth, some others believe it was 2 BC, saying that Herod died in early 1 BC. So again, this is two or three years after the other date. If Christ was born in 2 BC, then He could have still been 33 when He died if His birthday was later than April.
As for the quotation, when St. Peter made his first public sermon on Pentecost, he referenced the prophet Joel, who said "the Sun shall be turned to darkness and the Moon into blood" as signs preceding the Day of the Lord, the New Covenant, accomplished by the Resurrection (Joel 2:31 and Acts 2:20). At least one Gospel mentions darkness happening when Christ died, an "eclipse" of the Sun (but not by the Moon, since Passover is always during a full Moon) (Luke 23:44-45). Maybe that darkness was a very dark cloud. On the other hand, a lunar eclipse that turns "the Moon into blood" could happen during Passover. One lunar eclipse happened on April 3, 33, but not on April 7, 30. The eclipse was partially visible from Jerusalem, so no wonder St. Peter chose to reference that passage from Joel if the crowd remembered how dark it was and how the Moon looked red in the hours after Christ's death.
Conclusion
The Passion, Death, and Resurrection are some of the most detailed events from the life of Christ. By assembling many clues, despite having no specific year mentioned in the Gospels, we can reasonably say that the Resurrection happened on April 5, 33 or maybe April 9, 30. I personally accept the date of April 5, 33 because of the lunar eclipse St. Peter seemed to reference. Therefore, this year, the day of the year we have Easter (April 5) very well could match the original day of the year on which Christ rose from the dead!
