A cooling apparatus and method are provided for cooling an electronic subsystem of an electronics rack. The cooling apparatus includes a local cooling station, which has a liquid-to-air heat exchanger and ducting for directing a cooling airflow across the heat exchanger. A cooling subsystem is associated with the electronic subsystem of the rack, and includes either a housing facilitating immersion cooling of electronic components of the electronic subsystem, or one or more liquid-cooled structures providing conductive cooling to the electronic components of the electronic subsystem. A coolant loop couples the cooling subsystem to the liquid-to-air heat exchanger of the local cooling station. In operation, heat is transferred via circulating coolant from the electronic subsystem and rejected in the liquid-to-air heat exchanger of the local cooling station to the cooling airflow passing across the liquid-to-air heat exchanger. In one embodiment, the cooling airflow is outdoor air.