Correlated Colour Temperature (CCT), or colour temperature, refers to the colour appearance of a light source. This is dictated by the proximity of the light sources chromaticity coordinates in relation to the blackbody radiator. Usually specified in Kelvin (K), the lower the Kelvin value, the warmer the light feels or appears, whilst a higher Kelvin indicates a cooler appearance.

Colour temperature is essential in creating the right atmosphere for an application. In hospitality applications for example, a warmer light which is typically around 2700 K, is ideal for restaurants and bars where the aim is to invite people in and create a cosy and relaxing environment for guests to enjoy. Whilst a cooler colour temperature is widely used for back of house areas, such as laundry rooms and kitchens, where people are working and need to be alert and focused.