Yavannië

The ninth month of the year, according to the calendars of Men, approximately equivalent to the Halimath of the Shire-hobbits, or (rather less exactly) to modern September. According to the King's Reckoning of old Númenor, Yavannië ran from modern 23 August to 21 September (though in fact the Númenóreans would usually have used the Sindarin name for the month, Ivanneth).

The King's Reckoning remained in use by the Exiles of Númenor in Arnor and Gondor, and the month was historically significant as the time in which Isildur made his fateful journey northward toward the city of Annúminas. He led his Men from Osgiliath on the fifth day of Yavannië, and marched through the Vales of Anduin while the month lasted. It was not until early the next month, Narquelië or Narbeleth, that he suffered the unexpected defeat known as the Disaster of the Gladden Fields.

When Mardil adjusted the calendars of the Dúnedain in III 2060, two millennia after Isildur's time, he introduced some changes to Yavannië. Other alterations to the calendar meant that the month now started a day earlier, on modern 22 August. On this new reckoning, the so-called Stewards' Reckoning, Yavannië was still thirty days in length, but it was no longer followed directly by Narquelië. Instead, Mardil introduced a new feast day, independent of any month. This was Yáviérë, a harvest holiday that followed immediately after Yavannië and was followed in turn by Narquelië.