Colour temperature is a method of describing the colour characteristics of light, usually either warm (yellowish) or cool (bluish) and measuring it in degrees of Kelvin (°K).
The easiest way to remember which colour is which is by remembering that the higher the number (of kelvin) the whiter the light.
You may also come across lights that do not state a colour temperature in K (numbers) but rather by description. This is confusing, as most would not know the difference between "Cool white" and "Daylight". If you are unsure it's important to ask, as making the wrong choice can lead to the wrong lighting outcome.
Colour Temperature and Mood
Just as paint colour can help determine an overall mood in a space, lighting colour temperature can be used to determine and/or enhance a mood. If the space is an intimate restaurant or a comfortable office setting, warmer colour temperature lighting (in the 2700‐3200K range) helps to convey a glow‐of‐the‐fire type lighting that may be associated with a soothing and calming environment. Conversely, if a bright and airy environment is the goal, such as in a cafeteria, classroom, lobby, general offices and certain retail stores, then cooler colour temperature lighting (in the 5500‐6000K range) helps to convey a sunny daylight type lighting that may be associated with nice outdoor conditions.
Below are some examples of spaces and colour temperate ranges:
300k - 2700k
4000k - 5000k
5000k - 6000k