1 Kings 12:26-33
Whereupon the king took counsel, and made two calves of gold, and said unto them, It is too much for you to go up to Jerusalem: behold thy gods, O Israel, which brought thee up out of the land of Egypt. And he set the one in Bethel, and the other put he in Dan. And this thing became a sin: for the people went to worship before the one, even unto Dan.
And he made an house of high places, and made priests of the lowest of the people, which were not of the sons of Levi. And Jeroboam ordained a feast in the eighth month, on the fifteenth day of the month, like unto the feast that is in Judah, and he offered upon the altar. So did he in Bethel, sacrificing unto the calves that he had made: and he placed in Bethel the priests of the high places which he had made. So he offered upon the altar which he had made in Bethel the fifteenth day of the eighth month, even in the month which he had devised of his own heart; and ordained a feast unto the children of Israel: and he offered upon the altar, and burnt incense.This tells us that when Jeroboam chose to fall into idolatry he created a major Feast Day for the Northern Kingdom on the 15th of Cheshvan, a month after Tabernacles. He was clearly making his own replacement for that Biblical Holiday, but it also basically corresponded to the Pagan Mid-Autum festival season, from which Samhain and our modern Halloween derive.
It's also two days before the Anniversary of the beginning of the Flood which if you read Genesis 7 and 8 you'll see it began on the 17th. Before Exodus 12 changed the calendar this month was the 2nd rather then 8th. Jubilees is apocryphal so I wouldn't build doctrine on it. But it's interesting that it says soon after the Flood Norah told his descendants to observe holy days on the New Moons of the 1st, 4th, 10th and 7th months (corresponding to the Equinoxes and Solstices), and additionally one on the 17th of the 2nd month, the anniversary of The Flood starting. This may have been a fanciful story they made to explain the origin of Pagan holidays.
People who believe in certain Lost Tribes becoming Europeans theories sometimes see the Celtic Samhain deriving from this directly, becoming dated where it is now when they switched from a Lunar to Solar calendar. I don't believe those theories (they're mostly advanced by Anit-Semites, but Britam is an exception to that), but I do believe the Tribe of Dan had an interesting history (part of it is them being connected to the Tutha De Danann, who are also said to have brought Samhain to Ireland), one of Jeorboam's major Calfs was set up in Dan. Bill Cooper dates the arrival of the Danann in Ireland to 701 B.C.
My interest in that theory derives in-part from the theory that the Antichrist might come from Dan (This was the nearly universal view of the Early Church Fathers). Jeroboam is also in a sense a Prototype of The Antichrist being given 10 Tribes as the Little Horn will be given 10 Kingdoms, and his Right Hand becoming "Dried up" (Zechariah 11:17). I agree with Chris White's theory that it's likely during the first half of the 70th Week The Antichrist may claim to be (or be claimed to be) Messiah Ben Joseph.
So it might be possible this date will be important Prophetically as well. It's also near the anniversary of The Flood, and Jesus said "As the days of Noah where, so shall the coming of the Son of Man be" A statement that I think means many things. It should also be noted that the 15th is believed to be the day Matthias father of the Maccabees died. And it's the day the Novemberpogrome happened, considered by many the start of the Holocaust.
Some have suggested a parallel between The Flood timeline and the Fifth Trumpet in Revelation 9. That the 40 days the smoke covers The Earth correlates to the 40 days of Rain. Which could mean it it's from the 17th of Cheshvan until during Chanukah. And the 5 months the weird Locusts are allowed to torment mankind ends on the 17th of Nisan, same day the Ark rested which I view as the day of Jesus Resurrection on First Fruits in 30 AD.
If the 2030-2037 70th Week theory I've considered is correct, that 5 month time period could correlate closely to the Lunar Eclipses that occur in October 2032 and April 2033. But that is a conjecture that could very likely be wrong.
1 Maccabees tells us Antiochus Epiphanes set up his Idol in The Temple on the 15th day of the 9th month. And then did the ritual formally consecrating it on the 25th ten days latter. Some people think that the Hebrew calendar is sometimes a month off. The Samaritans and Karaites indeed are often observing everything a month later. It's later then the Hasmonean time the Calender entered it's current system (attributed to Hillel The Eldar). But the origin of this potential margin of error really is from the days of Hezekiah at the latest. So maybe the original Abominaiton of Desolation was set up on the Feast of Jeroboam?
I still however do not doubt the 9th month is the when The Temple was rededicated 3 years latter. Chris White's Daniel 8 study on the 2300 Morning and Evening Offering suggests a good reason for a month discrepancy occurring during that time. Hosea 2 predicts the 24th of Kislev to be a time for rededicating The Temple.
The 2300 mornings and evenings is 3 years and 1 month. So that fits also.