On the 27th of Cheshvan, one year after the beginning of the great flood, the earth dried and haShem commanded Noah to “Come out of the ark” and repopulate the world.
“And G-d spoke to Noah saying: “Go out of the ark, you and your wife, and your sons, and your sons’ wives with you. Every living thing that is with you of all flesh, of fowl, and of animals and of all the creeping things that creep on the earth, bring out with you, and they shall swarm upon the earth, and they shall be fruitful and multiply upon the earth.” (Breishit, 8:15-17).
The total time that Noah spent in the ark was 365 days – one solar year, or one year and 11 days on the lunar calendar.
Note: this chronology follows the opinion of the Talmudic sage Rabbi Eliezer. The chronology of the Flood indicated by the dates and time periods given in the Torah can also be found in Rashi’s commentary to the book of “Breishit” (chapter “Noach”).