Disclosed is a lighting unit (10) that utilizes sensor data to select a fade-in or fade-out profile for one or more light sources (12). The lighting unit includes a clock module (20), an ambient light level sensor (18), and a controller (16). The controller receives ambient light level data from the ambient light level sensor and time of day data from the clock module, and utilizes the received information to automatically select a fade-in or fade-out profile. The controller can also use the received ambient light level data to calibrate the clock module.