Expositor's Bible Commentary Commentary John 6:18

"And the sea was rising by reason of a great wind that blew." — John 6:18 (ASV)

The Sea of Galilee is six hundred feet below sea level, in a cuplike depression among the hills. When the sun sets, the air cools; and as the cooler air from the west rushes down over the hillside, the resultant wind churns the lake. Since the disciples were rowing toward Capernaum, they were heading into the wind; consequently, they made little progress.