You can visit the Galapagos any time of the year as there is always something wonderful happening in the Islands, especially with wildlife’s behavior and natural events.
From mid-June to early-December you have a mixture of warm and rain (afternoon showers), and Ocean waters are warmer and calmer due to the “El Niño” current. From mid-December to early-June is the cool/dry season on land and Ocean, especially because of the passing of the “Humboldt” current through the Archipelago.
Galapagos is a top-destination for travelers, therefore cruises and tours are on very high demand year-around. It is recommended to arrange your trip at least with 6 months in advance to secure and guarantee your spots on the preferred trip.
Now, if you find the opportunity to visit the Galapagos before 6 months in advance, there is also the possibility to find cruise deals that may fill your expectations. However, if you leave your decision for the last-minute, you may not find what you were looking for a tour that will fulfill your expectations.