And in the second month, on the seven and twentieth day - From this it appears that Noah was in the ark a complete solar year, or three hundred and sixty-five days; for he entered the ark the 17th day of the second month, in the six hundredth year of his life, Genesis 7:11, Genesis 7:13, and continued in it till the 27th day of the second month, in the six hundredth and first year of his life, as we see above. The months of the ancient Hebrews were lunar; the first six consisted of thirty days each, the latter six of twenty-nine; the whole twelve months making three hundred and fifty-four days: add to this eleven days, (for though he entered the ark the preceding year on the seventeenth day of the second month, he did not come out till the twenty-seventh of the same month in the following year), which make exactly three hundred and sixty-five days, the period of a complete solar revolution; the odd hours and minutes, as being fractions of time, noncomputed, though very likely all included in the account. This year, according to the Hebrew computation, was the one thousand six hundred and fifty-seventh year from the creation; but according to the reckoning of the Septuagint it was the two thousand two hundred and forty-second, and according to Dr. Hales, the two thousand two hundred and fifty-sixth. See on Genesis 11:12 (note).

And in the second month, on the seven and twentieth day of the month,.... This was the month Marchesvan, as the Targum of Jonathan, which answers to part of our October, and part of our November; though according to Bishop Usher (y), this day was Friday the eighteenth of December, A. M. 1657; it was on the seventeenth of this month that Noah went into the ark, Genesis 7:11 so that be was in it twelve months and ten days, according to a solar year; but if the reckoning is made according to Jewish months, six of which consisted of thirty days, and six of twenty nine only, then the twelve months made but three hundred and fifty four days, add to which eleven days to the twenty seventh, fully ended, it makes three hundred and sixty five days; so that he was in the ark just a full year, according to the course of the sun; but it seems very plain that the months here reckoned consisted of thirty days, since the one hundred and fifty, days when the waters abated are reckoned, from the seventeenth day of the second month, to the seventeenth day of the seventh month; which make exactly five months, and allow thirty days to a month: and at this time, when Noah had waited almost two months, after he had removed the covering of the ark:
was the earth dried; so that it was fit to walk upon, and was become commodious both for man and beast: a different word from that in the preceding verse is here used for "dry", this being a different kind, or, however, a greater degree of dryness than the other.
(y) Ut supra. (Annales Vet. Test. p. 4.)

The earth was dried - So as to be a fit habitation for Noah.