Ocean Currents and Conditions:

Peru Oceanic Current: The Peru Oceanic Current is part of the system called the Peru Current. It flows northwesterly carries ~20-24°C saltwater to the Galápagos. It turns westward and joins the South Equatorial Current (SEC) upon reaching the equator. (pp. 14-16)

Peru Coastal Current (Humboldt Current): This current is also part of the Peru Current. It consists of cool water (as low as 15°C) travelling northwest to the Galápagos, and extends about 700 km from the Peruvian mainland. It enters the SEC at approx 5° S. (pp. 14-16)

South Equatorial Current (SEC): This gigantic current is fed in part by the Peru Current. It originates just east of the Galápagos, and crosses the entire length of the Pacific. (pp. 14-16)

Equitorial Undercurrent (EUC, Cromwell Current): This is a subsurface current that flows from west to east toward the Galapagos Islands. It is only about 200 m wide. As it approaches the Galápagos, it rises, bringing its cool, nutrient-rich water to the surface. (pp. 16-17)

Panamá Current: Tropical Waters from Panamá flow southwest to the Galápagos. Periodically, due to complicated oceanographic circumstances, the Panamá current becomes stronger and a local (not global) El Niño phenomenon occurs. (pp. 17)

Of Note: Inshore Currents also occur within the Galapagos Islands. They generally flow in a northwesterly or southwesterly direction, though they also have a westerly component. They were studied over the Onslow Island Coral reef, where they ranged between 35.0 and 58.3 cm/sec during the period from low to high tide, and the tides they caused tended to fall in the area of 19-some meters. (pp. 17-18)

A Note on Currents and Weather: The interactions between the cool EUC and SEC and the warm Panamá current create extensive cloud cover with little or no precipitation. (pp. 17) 

Water Temperature: San Cristóbal contains some of the cooler water in the Galápagos. Temperatures in Wreck Bay “may be abnormally cool and subject to rapid temperature changes. (pp. 24-25)


Source:

Glynn, Peter W., Wellington, Gerard M., Wells, John W. Corals and Coral Reefs of the Galápagos Islands. University of California Press: Berkeley, CA; 1983.