170 days and 17 weeks are associated with ealy rain. 320 days and 8 weeks are associated with the season of latter rain. Shevat 15 was considered the New Year's Day for Trees because most of the annual rains occurred before Shebat 15, so that the trees which blossom afterward were considered as belonging to another year (latter rain fruit harvested celebrated in Tishri - See Note 1) .

Leviticus 23:39 Also in the fifteenth day of the seventh month, when ye have gathered in the fruit of the land, ye shall keep a feast unto the LORD seven days: on the first day shall be a sabbath, and on the eighth day shall be a sabbath.

• Hillel reasoned that the 15th of the Tu B'Shevat) was the New Year for Trees with respect to the tithe, Leviticus 27:30. A tenth each year whether of the seed of the land, or of the fruit of the tree was a tithe unto the Lord. Because the school of Hillel is considered the standard authority, the 15th of Shebat was observed as a semi holy day.
• The is celebrated in the seveneth month Tishri, which is the begining of a new civil year

In Zechariah 1:7- 8, the vision the Lord gives to Zechariah, we see a correlation of Sebat (Shevat) 25 with the New Year's Day for trees. The Red Horse (Satan) stood among in the myrtle trees on Sebat 24. The rise of Satan to power in 1988 to his complete control in 1994 is identified with the season prior to the start of the latter rains. A Final Harvest (latter rain fruits) is dictated outside the physical churches once the Red Horse (Satan) gains complete control of physical organized churches the true believers are driven out (killed, see Revelation 6:2-4) of the physical organized and are the seed of the latter rain harvest (See Note 2).

John 12:24 Verily, verily, I say unto you, Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit.

Romans 9:29 And as Esaias said before, Except the Lord of Sabaoth had left us a seed, we had been as Sodoma, and been made like unto Gomorrha.

Romans 9:28 For he will finish the work, and cut it short in righteousness: because a short work will the Lord make upon the earth.

• latter rains are essential for the latter rain harvest to be completed
• water as saving to Noah:
• 1Peter 3:20 Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
• latter rain months however also serve as storm (Spiritual Flood) that brings judgment upon the physical organized churches
• water as judgement to the unsaved:2Peter 2:17 These are wells without water, clouds that are carried with a tempest; to whom the mist of darkness is reserved for ever.

Zechariah 1:7 Upon the four and twentieth day of the eleventh month, which is the month Sebat, in the second year of Darius, came the word of the LORD unto Zechariah, the son of Berechiah, the son of Iddo the prophet, saying,

Zechariah 1:8 I saw by night, and behold a man riding upon a red horse, and he stood among the myrtle trees that were in the bottom; and behind him were there red horses, speckled, and white.

Revelation 6:2 And I saw, and behold a white horse: and he that sat on him had a bow; and a crown was given unto him: and he went forth conquering, and to conquer.

Revelation 6:3 And when he had opened the second seal, I heard the second beast say, Come and see.

Revelation 6:4 And there went out another horse that was red: and power was given to him that sat thereon to take peace from the earth, and that they should kill one another: and there was given unto him a great sword.

The latter rain is also identified with Adar 1, see link for related studies:

The month of Adar signifies the start of a Spiritual Flood and the month of latter rain (saving gospel water), summer (the absence of rain ) and winter

Spiritual Significance for 1978 years between 34 AD to 2012 AD

The 2nd Temple in Jerusalem was 46 years in building which spiritually represented the 1st and 2nd coming of Christ.

John 2:20 Then said the Jews, Forty and six years was this temple in building, and wilt thou rear it up in three days?

Christ also represented the coming of latter rain. The Final Harvest Temple is completed spiritually 46 years from the coming of Christ (the latter rain). The latter rain is identified beginning on Adar 1, there are 43 days from Adar 1 to Nisan 14 (Passover).
 

Christ was crucified during the Passover season in AD 33. The Pentecost Harvest is followed the day after Passover (Feast of Unleavened Bread) and 49 days. The following day /year after 33 AD would be 34 AD. The 49 forty -year periods would typify the completion of the Pentecost Harvest.

When we observe the probable beginning time frames for the Spiritual 4 months (Beginning Summer to Ingathering of Fruits) - in relationship to normal harvest cycles of 40 years cut righteously (multiplied by fractions of 1/3 and 1/2) a pattern pointing to the year 2012 as the Final Year in the Season of Harvest can be seen.