This new article explores the predictability of Antarctic sea ice, which varies by region and is influenced by ocean and atmospheric conditions. Using climate models, Marika Holland and co-authors, confirm that sea ice changes can be predicted months in advance, with cycles of predictability linked to ice growth and retreat: it remains predictable during growth, loses predictability when melting, and regains it as it reforms. Ocean temperature patterns near the ice edge play a key role, with variations across different regions. These ice changes also influence marine ecosystems by affecting light availability. Understanding these patterns can improve climate predictions and support the management of the Southern Ocean’s biodiversity.