Red sky at morning, sailor take warning. Red sky at night, sailor's delight.This is accurate in mid-latitudes, including the Mediterranean world. At sunset, these conditions imply a zone of dry, high pressure between you and the sun. Since weather in the mid-latitudes moves mainly west to east, that means a day of clear sailing. The opposite advice applies near the equator and the poles.
Now that the Messiah has been rejected, the repetition of the sign makes the prophetic doom of the Jewish nation certain. Jonah traveled 3 days to warn Ninevah that judgement was coming in 40 days. Jesus travelled 3 years to warn Judah that judgement was coming in 40 years. Jonah had been preaching to Israel, but they did not repent. He was then sent to preach to the gentiles of Ninevah, and they repented from the king down to the animals. Jesus was sent first to the "lost sheep of the house of Israel".
The Jews were called to be a light to the gentiles, but they hated and despised the gentiles, and were sentenced to death as a nation. Jonah was called to give light to gentile Ninevah, but hated and despised them, and was sentenced to death. But Jonah's life was preserved in the midst of the waters, and Israel has been preserved in the midst of persecution.