How many days of rain does the Genesis flood account describe for Noah's Ark?

The Genesis flood account describes rain falling for forty days and forty nights.

Genesis 7:12 uses this phrase when describing the rain that fell after Noah, his family, and the animals entered the ark. The number forty is also common in biblical narratives, where it can mark a substantial period of testing or transition.

The forty days of rain are not the same as the total time that Noah and the animals remained aboard. Genesis says the waters continued to prevail afterward, and the complete sequence—from entering the ark until leaving it—lasted much longer.

This distinction is a frequent source of confusion. The account separately describes the rain, the rising and prevailing waters, the waiting period before the mountains appeared, and the eventual drying of the earth.