Changes to the operating temperature of a LED may also cause a color shift in the emitted light. Different colors of white light are conventionally described using a color temperature scale stated in the unit of absolute temperature, the Kelvin, having the unit symbol K. Color temperatures over 5000 K are called cool colors (bluish white), while lower color temperatures (2700–3000K) are called warm colors (yellowish white through red). An incandescent light bulb emits light with a color temperature of approximately 2700 to 3300 Kelvin, while the color temperature of daylight ranges from 5000 to 6500 Kelvin depending on weather conditions and the time of day.

