Some Biblical commentaries and books that mention God's Annual Holy (Feast) Days often offer general periods when these feasts occur. They usually list Passover as observed within a March to April time frame, Pentecost taking place between May and June, and so on. This article will reveal the historically earliest and latest dates these Holy Days have occurred based on an analysis of all such dates in the Hebrew (Biblical) calendar from 3761 B.C. to the present.
Calendar Basics
We need to cover a few Biblical calendar basics before revealing the results of the research. The Hebrew (Biblical) calendar relies on a repeating time cycle of 19 years. An individual "normal" year can contain 353, 354 or 355 days while leap years can possess 383, 384 or 385 days.
There are two major factors that can affect when the Feast (Holy) days can occur. The first is the potential delay of the start of a Hebrew civil year (Tishri 1 / Feast of Trumpets) by up to two days due to the Hebrew calendar's postponement rules.
The second factor contributing to the movement of dates of God's Feast Days is the addition of a leap month. When a leap month of 30 days is inserted in the calendar it is called Adar I. The usual month of Adar, which always contains 29 days, is then renamed Adar II. Leap months, which are thirty days in length, are added in years 3, 6, 8, 11, 14, 17 and 19 of the Hebrew calendar's 19-year time cycle.
Passover
The earliest start of Passover that has ever occurred (the Feast of Unleavened Bread immediately follows it) was at sunset on March 13. This date was within year 16 of the Hebrew (Biblical) calendar's nineteen-year time cycle. This early feast date took place in 1348, 1405, 1481, 1500 and 1576 A.D.
The historically latest start for Passover has been at sunset on April 28 (within year 8 of the nineteen-year cycle). This date for the feast occurred in 3696, 3677, 3658 and 3430 B.C.
The above results mean that Passover can be observed within a range of 47 days (just short of seven complete weeks).
The most frequent time period for the celebration of Passover is from sunset Sunday to sunset Monday (Biblical days begin and end at sunset). The second most frequent period is from sunset Tuesday to sunset Wednesday.
Pentecost
Pentecost is always observed from sunset Saturday to sunset Sunday. The earliest start ever for this Holy Day was at sunset on May 2 (within year 16 of the calendar's nineteen-year time cycle). This early start took place in 1405 and 1500 A.D.
The historically latest start for Pentecost was at sunset on June 22 (within year 8 of the nineteen-year time cycle). This delayed onset of the High Holy Day happened only in 3677 and 3430 B.C.
The above results mean that Pentecost can be observed within a unusually large range of 52 days.
Feast of Trumpets
The Feast of Trumpets, which falls on Tishri 1 on the Hebrew calendar, marks the start of the Hebrew civil year. It also marks the beginning of another year in the calendar's nineteen-year cycle.
The earliest start ever for the Feast of Trumpets was at sunset on August 24 (within year 17 of the Hebrew calendar's time cycle). This feast began at this time in 1348, 1405, 1481, 1500 and 1576 A.D.
The latest start for the observance of Trumpets was at sunset on October 9 (within year 9 of the calendar's time cycle). This early observance took place in 3696, 3677, 3658 and 3430 B.C.
The above results mean that Trumpets can be observed within a range of 47 days. Trumpets holds the distinction of being the only Holy (Feast) Day that can potentially fall within three Julian / Gregorian months (August, September and October).
The most frequent time period for Trumpets to occur is from sunset Wednesday to sunset Thursday. The next most frequent period is from sunset Friday to sunset Saturday.
Day of Atonement
The earliest start of the Day of Atonement, throughout history, was at sunset on September 2 (within year 17 of the time cycle). This early date took place in 1348, 1405, 1481, 1500 and 1576 A.D.
The latest start for Atonement was at sunset on October 18 (within year 9 of the calendar's time cycle). This took place in 3696, 3677, 3658 and 3430 B.C.
The above results mean that Atonement, like many of the other Feast days, can be observed within a range of 47 days.
The most frequent time period for Atonement to occur is from sunset Friday to sunset Saturday, with sunset Sunday to sunset Monday being the second most popular.
Feast of Tabernacles
The earliest start date ever for the Feast of Tabernacles (the High Day known as the Last Great Day follows the seven-day celebration) was at sunset on September 7 (within year 17 of the calendar's time cycle). This early celebration of the most joyous of God's Holy Day periods took place in 1348, 1405, 1481, 1500 and 1576 A.D.
The latest start date for this Feast was at sunset on October 23 (year 9 of the Hebrew calendar's 19-year time cycle). This late date occurred in 3696, 3677, 3658 and 3430 B.C.
The above results mean that this glorious holy Feast can begin within a range of 47 days.
The most frequent time for the first day of the Feast of Tabernacles is from sunset Wednesday to sunset Thursday. The second most frequent weekly start is from sunset Friday to sunset Saturday.
Miscellaneous Trivia
The Feast of Trumpets (Tishri 1), from the start of the Hebrew civil calendar in the fall of 3761 B.C. to 2024 A.D., has not been postponed 2,260 times. Tishri 1 has been postponed, however, one day 2,715 times and two days 810 times.
The postponement rules that govern the Hebrew (Biblical) civil calendar prohibit the declaration of Tishri 1 to certain days. The first day of the year can only fall on a Monday, Tuesday, Thursday or Saturday. It is prohibited from falling on a Sunday, Wednesday or Friday.
The Day of Trumpets in 2016, which fell on October 3, marked the end of Hebrew year 5776 and the start of year 5777. This day was not only the end of a 19-year time cycle, it also signified the 304th complete 19-year time cycle of the calendar.