A sensor assembly for a vehicle includes a base, a sensor body mounted to the base and rotatable relative to the base around an axis in a direction of rotation, and a cover. The sensor body includes a sensor window and a wall having heat fins elongated circumferentially relative to the axis. The cover is positioned to cover the heat fins. The cover includes an inlet open in the direction of rotation. The cover defines an airflow path from the inlet through the heat fins. The cover includes an outlet positioned to direct air across the sensor window.