The Seventh Hebrew month is called Tishri (counting from Nisan) and usually falls on the Gregorian calendar during the months of September/October.
Even though the agricultural/Biblical calendar begins in the spring, in the month of Nisan, modern Judaism celebrates Rosh Hashanah (head of the year) beginning on the first day of Tishri. It is their new year according to the civil calendar. The holiday is traditionally celebrated for two days. In the Bible, years of Jubilee/Shemitta are calculated according to the civil calendar.
The Biblical name of the holiday which begins on Tishri 1 is called Yom Teruah (Day of Trumpets) and it is observed at the sighting of the new moon of the 7th month. Like Rosh Hashanah it was traditionally celebrated for two days.
Yom Teruah marks the beginning of a ten day period known as the "10 days of awe" which is a time for self-examination, prayer, and repentance which culminates on Yom Kippur (Day of Atonement) on the 10th day of the month. These 10 days were days of teshuvah (repentance).
According to Jewish tradition, the universe was created on Tishri 1 (or on Elul 25th so that Rosh Hashanah would mark the 6th day of creation, and the day when God created Adam and Eve).
Yom Teruah is also referred to as "Yom ha-Zikaron" (the day of remembrance) in that we were to remember to blow the shofar. The Bible gives little detail as to why the shofar was to be blown or what was to be remembered. We do know that it was known as a day for the coronation of kings. I believe, as do others, that one day in the future Yeshua will be crowned as King of kings and Lord of lords on this day.
Tishri is a month full of holy days.
Tishri 1 (Yom Teruah) is a high holy day (a Sabbath day).
Tishri 10th is Yom Kippur/ Day of Atonement (a high Sabbath)
Tishri 15th - 21st is Sukkot/Tabernacles. The first day of Sukkot is a high Sabbath also.
Tishri 22nd is a high Sabbath called Shemini Atzeret (Eighth Day).
The first of the month was a time for repentance which culminated on the day of judgment, Yom Kippur, when the fate was sealed. Following this time of judgment came Sukkot which was known as, The Season of Our Joy! The Eighth Day (Shemini Atzeret) was the day that all firstfruits of the fall harvest were brought to the LORD and prayers for rain began for the coming year.
As Yeshua came the first time during the spring feasts and brought them to a higher level of understanding, it is likewise believed that He will return during the fall feasts. All of the fall appointed times show us a picture of His coming as King and a bridegroom ready to receive His bride to Himself. He will at that time pour out His wrath upon the wicked while He protects His children who have been found faithful.
For a more complete and detailed explanation of the holidays contained within this month please see the articles attached below or visit the tab "Appointed Times" on the home page of the website. Additional articles on the Appointed Times (Moed) can be found under the tab "feast teachings".