The diving season in Galapagos is year round. There are two distinct seasons depending on what you want to see though. The warm season from December to May is the best for schooling hammerheads and other sharks like silkies. The conditions are also better with less waves and milder currents and the visibility is much better too. During the cold season in July to December, temperatures drop to 16-18°C/60-65°F. This is whale shark season, when nutrient rich currents bring these giants to the islands. Darwin and Wolf are particularly good spots for spotting whale sharks travelling on the currents. This cooler period is a great time to see penguins and mola mola too.