창세기 8:14 주석: Rashi, Radak, The Midrash & Rabbeinu Bahya

בשבעה ועשרים ON THE TWENTY-SEVENTH [OF THE MONTH] —The rain had begun to fall in the second month on the seventeenth day (Genesis 7:11): the ten days are those by which the solar year exceeds the lunar year; for the punishment of the generation of the Flood lasted a full (i.e. a solar) year (Genesis Rabbah 33:17).

ובחודש השני בשבעה ועשרים יום לחודש, this is the month of Marcheshvan Our sages (at the end of section 33 of Bereshit Rabbah say that these 10 days represent the 10 days which the solar year is longer than the lunar year.