וַֽ֠יְהִי בְּאַחַ֨ת וְשֵׁשׁ־מֵא֜וֹת שָׁנָ֗ה בָּֽרִאשׁוֹן֙ בְּאֶחָ֣ד לַחֹ֔דֶשׁ חָֽרְב֥וּ הַמַּ֖יִם מֵעַ֣ל הָאָ֑רֶץ וַיָּ֤סַר נֹ֙חַ֙ אֶת־מִכְסֵ֣ה הַתֵּבָ֔ה וַיַּ֕רְא וְהִנֵּ֥ה חָֽרְב֖וּ פְּנֵ֥י הָֽאֲדָמָֽה׃
Und im sechshundertundersten Jahre, am ersten Tage des ersten Monats, war das Wasser von der Erde geschwunden; da nahm Noah die Decke der Arche ab und sah, dass die Oberfläche des Erdbodens trocken war.
Rashi on Genesis
בראשׂון IN THE FIRST MONTH — According to R. Eliezer this would be Tishri, and according to R. Joshua Nisan (Rosh Hashanah 11b).
Sforno on Genesis
ויסר נח את מכסה התבה, he had thought that the earth had already dried out completely only to find
Radak on Genesis
[Began] to dry. It was still like mud, dry on the surface but soft underneath. Noach knew that Hashem would tell them when it was safe to go out.