It was at the end of forty days that Noah opened the window of the ark that he had made.
Genesis 8:6 TLV

The word for window here is khalon and not arubah as in v2. It is still interesting that the windows of the ark are opened as the windows of heaven are closed. This points to the way in which God shelters his people from the full force of his wrath. It rains down around them, but they are hidden by their obedience to his instructions.