An LED lamp and method are provided for autonomously changing the output brightness and color temperature of a plurality of LED strings to follow a first dimcurve in temporal synchronization with at least one other LED lamp. Synchronization is achieved based on a time of day determined using a clock signal. The output brightness and color temperature can transition from the first dimcurve to a second dimcurve over a predetermined number of scenes. The number of scenes is a function of a difference between the first dimcurve and the second dimcurve in at least one of the output brightness and the color temperature.