In the articles Jesus crucified the day before a high Sabbath, Doctrines that creep in: Palm Sunday was on a Sunday, and The fulfillment of the sign of Jonah, Scriptural evidence was presented and examined to demonstrate that the traditional view of Jesus' crucifixion occurring on a Friday is incorrect, rather it actually occurred on a Thursday.
It is easy to think Jesus was crucified on a Friday because Scripture reveals the day after Jesus' death was a Sabbath and all Saturdays are Sabbath days. However, the articles demonstrate that regardless of which day of the week Passover falls, the following day will always be a Sabbath day because it is the first day of the Feat of Unleavened Bread. John's Gospel reveals that Sabbath was a “high day,” thus it wasn't just an ordinary Saturday Sabbath.
A crucifixion on Thursday is the only day of the week that works with all Biblical accounts of the crucifixion. Jesus was in the grave “three days and three nights.” From Thursday just before sunset to Sunday just before sunrise includes three days and three nights. A Friday crucifixion only gives 2 days and 2 nights. A Wednesday crucifixion gives 3 full days and 3 full nights, but that means the empty tomb was revealed and the conversation on the road to Emmaus occurred on the fourth day. A Thursday crucifixion gives 3 days (Thursday before sunset, Friday, and Saturday) and 3 nights (Thursday night, Friday night, and Saturday night). The third day after Thursday is Sunday. Thursday explains why all of the gospel writers used the plural form, “Sabbaths.” And, a Saturday Triumphant Entry means a Thursday crucifixion.
But secular history has to be checked to see if there actually was a Thursday Passover day during the time when Pontius Pilate was governor and during the time of Jesus’ ministry. Tiberias Caesar became emperor of Rome on A.D. August 19, 14. He appointed Pilate as governor in A.D. 26 for a term of ten years.  Luke chapter 3 tells us that John the Baptist’s ministry began and Jesus’ baptism occurred “in the fifteenth year of the reign of Tiberius Caesar.” Tiberias’ 15th year began on A.D. August 19, 28 and ended one year later on A.D. August 18, 29. If Jesus’ first Passover was in A.D. 29, and two more Passovers are added, then Jesus died on the Passover in A.D. 31.  That is a year in which Pontius Pilate was governor and it is a year that had a probable Thursday Passover date of April 26th. Bear in mind, the Jewish day began the night before at sundown – in this case April 25th.
There is more evidence that 31 A.D. was the year of Jesus’ crucifixion.
There are references in the Jewish Talmud that refer to mysterious events that occurred “40 years before the destruction of Jerusalem.” One of the strange things they recorded had to do with the celebration of Yom Kippur (the Day of Atonement) in the fall.  The following is from the Talmud:
(Yoma 39b) Our Rabbis taught: During the last forty years before the destruction of the Temple the lot (‘For the Lord’) did not come up in the right hand.
During the annual Day of Atonement, two identical male goats were used for the removal and forgiveness of sins. (See Leviticus 16:5-10.) The High Priest was to “cast lots upon the two goats; one lot for the LORD, and the other lot for the scapegoat.” The sins of the people were placed upon the head of the scapegoat that was to “be presented alive before the LORD, to make an atonement with him, and to let him go for a scapegoat into the wilderness.” The other “goat upon which the LORD’s lot fell” was to be offered as a sin offering.
During the second Temple times, a white stone representing the goat for the Lord and a black stone representing the scapegoat were used for the purpose of casting lots. The lot chosen determined which of the two goats would be “for the Lord” and which goat would be the “scapegoat.” For two hundred years, the High Priest selected a black stone as often as a white stone. But then, ominously, for forty years in a row prior to the destruction of Jerusalem by the Romans, the High Priest always picked the black stone. The Jewish religious leaders saw this as God’s rejection.  Ernest L. Martin in the latest edition of his book Secrets of Golgotha asserts that the rabbis knew the fist black stone was pulled about the time Jesus had been crucified. 
Since Jerusalem was destroyed in A.D. 70, the last black stone would have been drawn in the fall of the preceding year, A.D. 69. That would be the last year the High Priests kept Yom Kippur in Jerusalem. Now counting backwards from the last black stone (the 40th stone), the 39th stone would have been drawn in the fall of 68, the 38th in 67, … the 31st in 60, … and the first black stone would have been drawn in the fall of 30 A.D. That suggests 31 A.D. was the year of the crucifixion.
Additional evidence that not only the year A.D. 31 was the correct year, but also supports a Thursday crucifixion can be found in the lunar tables. On the night Jesus prayed in the Garden of Gethsemane (Wednesday, A.D. April 25, 31), there was an eclipse of the moon.  One Biblical commentator (Olaf Hage) believes Jesus’ sweat drops would have glistened in the red light of an eclipsed moon. The disciples would metaphorically recall the scene of the huge sweat drops on Jesus’ face as appearing like great drops of blood. (Notice in Luke 22:44, the Bible doesn’t say Jesus sweat actual drops of blood, but “his sweat was as it were great drops of blood falling down to the ground.”)
If this is the case, it gives insight as to how Peter on the Day of Pentecost could proclaim the prophecy from the book of Joel was fulfilled. He saw the moon turn the color of blood during the lunar eclipse the night Jesus was arrested and then he saw the sun turned into darkness on the day of Jesus’ crucifixion. (See Acts 2:20 and Joel 2:31.) It should be noted that there was no other visible, springtime, lunar eclipse over Jerusalem during the time Pilate was governor. 
With a standardized calendar, mathematical algorithms based upon astronomical tables can determine the first of Nisan not only for the future, but for the past as well. The most important requirement for Nisan was and is to ensure that the Feast of Unleavened Bread falls in the spring. That’s where the year A.D. 31 is interesting.
Computer calculations based upon the astronomical tables fix the 1st of Nisan in A.D. 31 as March 13th, Passover as March 26th, and the first day of the Feast of Unleavened Bread as March 27th. The first day of spring (called the vernal equinox) was March 23rd in that year. The computer satisfies the springtime requirement for the Feast of Unleavened Bread. 
However, the Jews did not use modern methods for determining when the new year would begin. For the Sanhedrin to declare rosh chodesh (first of the month) for Nisan on A.D. March 13, 31, they would have had to inspect the barley fields in the early part of March and gain confidence that there would be enough ripe barley available to be offered over 2 weeks later.
We cannot determine today the condition of the barley crop in early March of A.D. 31, but it appears from the accounts of travelers during that era that barley became ripe in the plains of Jericho by the beginning of April.  So unless they had a mild winter, the sure probability of the barley crop was sufficiently advanced to reach abib at this point would be in doubt. Considering that meeting the requirements of Leviticus would be of more importance than rushing into declaring the month of Nisan too early, they would be more prone to declare a second month of Adar – thus making this a "leap year" by delaying the month of Nisan for another cycle of the moon. Therefore, it is reasonable to expect that the declaration of the first of Nisan would have waited until the appearance of the next first crescent moon, setting the first of Nisan as April 12th.
However, the first crescent moon of April 12th didn’t rise for over an hour after sunrise and would not have been visible until after sunset on the 12th.  Since that is after sunset, it’s a new day and thus rosh chodesh would have been proclaimed for Nisan the night of April 12th/day of April 13th, which would have placed Passover on the night of April 25th/daytime of A.D. April 26, 31 – a Thursday.
Is there evidence from the Bible to indicate that this was a "leap year" - a year with a late Passover date? Yes, there is. On the day after His Triumphant Entry, Jesus cursed the fig tree. In the spring, no fig tree in Israel is bearing. The normal, full leaf and fruit-bearing season for fig trees was June. Even though this tree must have been faulty – to be in leaf without fruit – the fact that it had leaves indicates summer was nearing. Furthermore, during this last week and while on the Mount of Olives, Jesus taught, “Now learn a parable of the fig tree; When her branch is yet tender, and putteth forth leaves, ye know that summer is near.” (Mark 13:28)  Chances are Jesus was pointing to a fig tree that was just putting forth its leaves. Jesus would not have found a fig tree in leaf had the Passover of A.D.31 been in March.
Therefore secular history confirms there was a Thursday upon which Christ's crucifixion could have occurred during the time Pilate was in office and Jesus was concluding His ministry on earth. Secular and Biblical evidence strongly indicate that A.D. 31 was the year of Christ's crucifixion.
 “Pontius Pilate”, Former Things, http://formerthings.com/pontius.htm
 “Year of the Crucifixion”, Harvard House, http://www.harvardhouse.com/prophetictech/new/year.htm
 Olaf Hage, “The Crucifixion Of Jesus”, Hage Productions, 1998, http://petragrail.tripod.com/tree.html
 Aaron Copeland, “Evidence in the Talmud for Jesus as the Messiah”, Aaron’s Place,
 Nicholas Federoff, “Talmudic Evidence for the Messiah at 30 C.E.”, Window View, 2005, http://www.windowview.org/jandg.files/frms/talmds.frm.html, January 30, 2009
 “Lunar Eclipse Page, NASA, http://eclipse.gsfc.nasa.gov/lunar.html
 “Calendar Stats”, The Shepherd’s Page, http://www.abdicate.net/cal.aspx
 Rev. Henry Browne, Ordo Saeclorum. A Treatise on the Chronology of the Holy Scriptures, pg. 466
 NASA solar tables http://aom.giss.nasa.gov/srlocat.html and lunar tables http://aom.giss.nasa.gov/moonloc.html. Jerusalem lat long is 32.05 N 34.48 E. The results must be adjusted by two days to agree with other NASA lunar tables (such as the NASA ellipse site in source  above), as these programs continue to account for the Gregorian calendar 400 leap year adjustment even though the Gregorian calendar was not in use at this time.
 “The history of the fig in the holy land from ancient times to the present day”, Economic Botany, Springer New York Volume 19, Number 2 / April, 1965
 Grace Ministries English Study Bible, first edition, notes to Matthew 21:19, pg. 62