Jesus is depicted dying on the Cross for our sins. In my opinion, it was dark when Jesus was crucified. The darkness signifies their cruelty towards Him as they did not know that He was the Son of God.
When Jesus ascended from the water, the heavens were opened unto Him—lo and behold, a voice from heaven declared that Jesus was the promised Saviour and the Spirit of God descended as a dove, alighting on Christ. “For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.” (John 3:16)
God was angry when people did bad things and He wanted to punish them. However, Uncle Noah was a good man who listened to God, and God protected Uncle Noah by asking him to build a big boat to keep him, his family and some animals safe. God set a rainbow in the sky after the flood, promising Uncle Noah that He would never flood the earth again.