How long was Noah on the ark?

A ship’s log

Genesis tells the flood like a captain’s logbook, dated by the age of Noah. The first entry is the day the water came.

In the six hundredth year of Noah’s life, in the second month, on the seventeenth day of the month, on that day all the fountains of the great deep burst open, and the sky’s windows opened.

That same day Noah, his wife, his sons and their wives were inside, with the animals (7:13–16). Then the entries follow, month by month.

The voyage, date by date

1. Seven days of warning. God says the rain will begin “in seven days” (7:4), and after them the water comes (7:10).
2. Year 600, month 2, day 17. The deep bursts open, the sky’s windows open, and God shuts the door (7:11–16).
3. Forty days. Rain falls forty days and forty nights and lifts the ship off the ground (7:12, 17).
4. 150 days. The water covers the earth for a hundred fifty days (7:24), then begins to go down (8:3).
5. Month 7, day 17. The ship comes to rest on the mountains of Ararat (8:4).
6. Month 10, day 1. The tops of the mountains appear (8:5).
7. Forty days later. Noah opens the window and sends out a raven (8:6–7).
8. Three weeks. The dove flies three times, seven days apart, and the third time she does not come back (8:8–12).
9. Year 601, month 1, day 1. Noah lifts the covering and sees the ground drying (8:13).
10. Month 2, day 27. The earth is dry, and God says, “Go out of the ship” (8:14–16).

How many days is that?

From the 17th of the second month to the 27th of the second month a year later: one year and ten days. The text itself hints at the length of its months. The water rises on the 17th of the second month, prevails 150 days, and the ship grounds on the 17th of the seventh: five months, exactly 150 days. That means months of thirty days, and a voyage of 370 days.

If the writer counted moons instead, a lunar year runs about 354 days. Add the days from the 17th to the 27th and the total comes close to 365, a full solar year. The medieval commentator Rashi drew that conclusion: the judgment on the flood generation lasted exactly one year of the sun.

In the six hundred first year, in the first month, the first day of the month, the waters were dried up from the earth. Noah removed the covering of the ship, and looked. He saw that the surface of the ground was dry.

Even then he waits almost two more months. Noah does not open the door himself. God shut it (7:16), and he leaves only when God tells him to (8:15–16).

Forty days was the rain

The number everyone remembers, forty days and forty nights, is the downpour, not the voyage. Counted from the first day, the water rules for five months and takes seven more to drain away. Many scholars think the text braids two older accounts: one counts in sevens and forties, with a short flood of rain and weeks of waiting with birds; the other keeps the dated year by Noah’s age. Woven together, they give the year Genesis reports. Traditional readers see one story, with the forty days inside the year.

Genesis gives no time at all for building the ship. Noah is 500 when his sons are born (5:32) and 600 when the rain begins. The 120 years of Genesis 6:3, often quoted as building time, are read by some as a limit on human life and by others as a countdown to the flood. For where the ship came to rest, see where Noah’s ark landed.