In this part of The Old Man and the Sea the old man is closely assessing the weather conditions around him. Santiago has analyzed everything from the pattern of the birds flying, to the way that the fish are jumping around. His connection to nature is so acute that he can already predict what will happen, what causes it, and the results of it.
Santiago now focuses on the wind. He can see the clouds forming, the direction to which the birds are going, and the direction of the breeze.
He looked at the sky and saw the white cumulus built like friendly piles of ice cream and high above were the thin feathers of the cirrus against the high September sky.
"Light brisa," he said. "Better weather for me than for you, fish."
He concludes that there is no hurricane coming. Moreover, he is enjoying the peaceful surroundings, and the breeze is a welcome addition. When he tells the fish that the light breeze is better weather for him than for the fish he is actually being humorous: he is saying basically that the weather is on his side, so he is going to be safe fishing. Contrastingly, the fish are not as safe because he is out there looking for them. In other hands, Santiago has now the upper hand.
While the old man is holding onto his fishing line, he attempts to take the pressure off of his left hand because it is beginning to cramp. After Santiago switches arms by holding the line with his right hand, he begins to muse about the clouds in the sky. Santiago assesses the weather conditions and understands that there is nothing to fear because weather during hurricane seasons is the best. Santiago also knows how to spot a hurricane coming while at sea. His thoughts reveal his experience and acute knowledge of his natural surroundings. Santiago feels at home on the open sea and is thankful for good weather conditions. He humorously says, "Light brisa. . . Better weather for me than for you, fish." Santiago's comment is a light-hearted statement that illustrates his favorable position. The light breeze represents the good weather conditions that aid Santiago in his mission. However, the favorable weather conditions for Santiago do not benefit the fish in any way. The positive weather conditions allow Santiago to continue holding onto the strong fish that he has caught.