Cocos Island is one of the world’s best dive sites at any time of the year.  However, there are some seasonal variations in weather and what you have the best opportunities to see.

The dry season runs from November to May during which you can expect calmer seas.  Pelagic highlights during this period include Silky Sharks and Mobula Rays which can accumulate in very large schools.  Water temperatures range from around 25 – 28 ^oC (78 – 82 ^oF)

The rainy season runs from June to November during which the seas can be rougher – something which can make the 30 to 36 hour liveaboard dive boat journey from the Costa Rican mainland to Cocos quite uncomfortable.  Schooling Hammerhead Sharks can be seen at any time of the year in Cocos, but the rainy season tends to attract larger schools.  This is also a better time of the year to sea Whale Sharks.  Water temperatures range from 24 – 27 ^oC (76 – 80 ^oF).

These dry and rainy seasons reflect the weather on the Costa Rican mainland.