The climate of Alonissos is Mediterranean, with rainy winter and dry summer. Average temperature of the island is 17°C. The main characteristic of the island is the limestone rocks, the high rocks that reach the sea and the caves, habitat of the Mediterranean seal Monachus monachus. Remarkable indeed, is the fact that approximately 2/3 of the world population of the Mediterranean seal is found in Greece. The island, like the rest of the Sporades complex, has remarkable flora and fauna. Among other things, the flora of Alonissos consists of pines, wild olives, maples, cypresses, shrubs such as koumaria, shinos, holly, fillyki, heather. It also has endemic plants such as Campanula reiseri and rechingeri, Linum gyaricum and Areanaria phitosiana. The orchids of Alonissos also stand out, even though their variety is limited compared to the rest of the Sporades. More generally, the island's flora is smaller compared to those of the other Sporades, perhaps because no major scientific research has been carried out there to date. The fauna of Alonissos is rich, consisting of about 300 species of fish, 80 species of birds, reptiles and mammals. Rare species that can be found in the area are the Mediterranean seal, the red coral, the black petrel, the eider gull, the cormorant and the Jura ibex. Birds such as the bald eagle, the cormorant, the herring gull, and the gray herons are also found in the area. The underwater fauna is also rich, as several species of dolphins and whales are found on the island.