But when they saw Him walking on the sea, they supposed that it was a ghost, and cried out; for they all saw Him and were terrified. But immediately He spoke with them and said to them, “Take courage; it is I, do not be afraid.” Then He got into the boat with them, and the wind stopped; and they were utterly astonished,
Mark 6:49-51 (NASB)
Cry out to Christ when darkness and clouds are present. His comforting voice and presence are enough to provide courage and calm the storm.