In Genesis, what is the stated duration of the rain during the Flood?

Genesis states that rain fell on the earth for forty days and forty nights during the Flood. This duration appears in the account after Noah, his family, and the animals enter the Ark.

The forty-day period refers specifically to the rain. Genesis also describes the waters remaining on the earth for a much longer span, so the rainfall duration should not be confused with the total length of the Flood narrative or the time Noah spent inside the Ark.

The number forty has recurring importance in biblical stories, including Moses’ time on Mount Sinai and Israel’s years in the wilderness. In Noah’s story, however, the phrase functions as a concrete time marker for the continuous rainfall. Later readers sometimes use “forty days” to describe the entire Flood, but Genesis distinguishes the rain from the subsequent recession of the waters.