There are no established tipping guidelines for all cruises, you should decide the amount to tip your guide and crew based on your level of satisfaction with the services provided on board and while on excursions.
On Luxury and First class cruises it is recommended to tip $15-$20 p.p. for the guide per day and the same amount per day for the whole crew. On Midrange and Economy class cruises it is recommended to tip $10-$13 p.p. for the guide per day and the same amount per day for the whole crew.
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.