13.5.2. Prophetic Year

Further, these 70 x 7 = 490 years can be shown to consist of exactly 360 days each. They are not based on the year of our modern calendar which is either 365 days (normal year) or 366 days (leap year) long. This reflects historical differences in how the calendar year has been adjusted to account for the fact that the astronomical year is not an exact number of days. The astronomical year consists of approximately 365 days. If we treated each year as exactly 365 days, the calendar date would slowly advance further and further ahead of the astronomical year becoming out of step with the seasons. We solve this inaccuracy by appending an extra day onto the month of February on leap year. However, in the past there have been different solutions employed for handling this problem:

With modern astronomy one can reckon a year very precisely as being ‘365.24219879 days, or 365 days, 5 hours, 48 minutes, 45.975 seconds.’ However, in ancient times various systems were used. When one investigates the calendars of ancient India, Persia, Babylonia and Assyria, Egypt, Central and South America, and China it is interesting to notice that they uniformly had twelve thirty-day months (a few had eighteen twenty-day months) making a total of 360 days for the year and they had various methods of intercalating days so that the year would come out correctly. Although it may be strange to present-day thinking, it was common in those days to think of a 360-day year.1

The more recent Jewish Calendar utilized a combination of the sun and moon:

It is called “lunar-solar” because it allowed the sun’s orbit to mark the years’ beginning but based the beginning of months on observation of the phases of the moon. The first appearance of the new moon would mark the new month. According to the Talmud, the priests would watch for this and proclaim it by sending messengers and blowing trumpets. The first problem is that the moon’s circuit is about 29 1/2 days, forcing a vacillation between a 30-day and a 29-day month; and second, that 12 of these moon/months equal 354 1/4 days, about 11 days short of the solar year. From the Babylonians the Hebrews learned to add an extra month every two or three years. In rabbinical times this “intercalary” month was inserted seven times in 19 years.2

Yet we have evidence from the time of Noah that months did not alternate in length between 30 days and 29 days. The book of Genesis indicates a 5-month period as being exactly 150 days in length, or five 30-day months:

The time measurements encountered in Genesis chapters 7 and 8 are the result of a lunar calendar. Gen. Gen. 7:11 states the flood began on the seventeenth day of the second month, and it ended on the seventeenth day of the seventh month (Gen. Gen. 8:4), exactly five months. Both Gen. Gen. 7:24 and Gen. 8:3 declare the waters were upon the earth 150 days. Assuming each month is the same length, they would have 30 days apiece. Skeptics say that is a big assumption because the story does not cover an entire year, and thus doesn’t take into account any days the ancients may have added on to their year.3

It appears that the earlier Jewish calendar may have been simpler than the “lunar-solar” system. “Ussher found that the ancient Jews and the Egyptians did not use a year based on the moon. Instead they had a year made up of 12 months, each 30 days long. At the end of the year they tacked on 5 days. Every 4 years they added 6 days.”4 We also have indication in Scripture that a simpler 360-day calendar is found within prophetic passages:
  • Daniel indicates a period of seven years as the final “week” of the seventy weeks, but which is divided in half (Dan. Dan. 9:24). The period of half of this final week of years is denoted by “time, times, and half” (Dan. Dan. 7:25; Dan. 12:7), or one, two, and one-half = 3.5 years.
  • John records the duration of the period during which Jerusalem will be trampled by the Gentiles as “forty-two months” (Rev. Rev. 11:2+). If twelve 30-day months are used, this period corresponds exactly to 3.5 years of 360 days each.
  • The two witnesses are said to prophesy for “one thousand two hundred and sixty days” (Rev. Rev. 11:3+) which is also exactly 42 months of 30 days each or 3.5 years of 360 days each.
  • The woman who flees from the dragon is fed by God for “one thousand two hundred and sixty days” (Rev. Rev. 12:6+) which is also described as “time and times and half a time” (Rev. Rev. 12:14+). Thus 1,260 days = 3.5 years of 360 days each.
  • The beast is given authority for “forty-two months” (Rev. Rev. 13:5+). This probably corresponds to the “one thousand two hundred and sixty days” during which the dragon persecutes the woman. It is also said to be “time and times and half a time” (Dan. Dan. 7:25). Thus 42 months of 30 days each = 3.5 years of 360 days each = 1,260 days.
When the various evidences are considered, it seems best to conclude:
  1. Daniel’s “weeks” are weeks of years.
  2. The prophetic year consists of 360 days.


1 Harold Hoehner, Chronological Aspects of the Life of Christ (Grand Rapids, MI: Zondervan, 1977), 135-136.

2 Trent C. Butler, Chad Brand, Charles Draper, and Archie England, eds., Broadman and Holman Illustrated Bible Dictionary (Nashville, TN: Broadman and Holman Publishers, 2003), 252-253.

3 Charles H. Ray, “A Study of Daniel 9:24-17, Part II,” in The Conservative Theological Journal, vol. 5 no. 16 (Fort Worth, TX: Tyndale Theological Seminary, December 2001), 321.

4 James Ussher, The Annals of the World (Green Forest, AR: Master Books, 1658, c2003), 114-115.