Definition
A measurement, expressed in degrees Kelvin (K), that describes the color characteristics of light produced by a source. It is based on the temperature to which a theoretical black body would have to be heated to emit light of that same color. Lower color temperatures (around 2,000–3,000 K) produce reddish or yellowish light; higher color temperatures (5,000 K and above) produce white or bluish light.
Plain English
A number, given in degrees Kelvin, that tells you the color tint of a light — low numbers look warm and yellow, high numbers look cool and blue.
Context Anchor
Seen in aircraft lighting, airport lighting, display lighting, and equipment specifications that describe how a light will appear to the eye.
Derivation
The term comes from physics: when a metal object is heated, it glows first red, then orange, then white, then bluish-white as its temperature rises. Scientists realized you could describe any light's color by the temperature of a heated object that would glow that same color. So the 'temperature' here isn't how hot the bulb is — it's the temperature of an imaginary glowing object that would match the color.
Why Pilots Care
Correct color temperature reduces eye strain, preserves night vision adaptation, and ensures accurate color recognition of instruments and external lighting during night or low-visibility operations.
Analogy
Think of a metal bar being heated. As it gets hotter, its glow changes from reddish to yellowish to white. Color temperature uses that same idea to describe the look of a light.
Intuition Check
Color temperature does not mean the physical heat of the light bulb or display. Here, temperature is a scale for the light’s color appearance.
Example Sentence 1
The new LED panel lights had a color temperature of about 3,000 K, giving the cockpit a warm tone that didn't interfere with night vision.
Example Sentence 2
Runway edge lights at 5000 K produce a crisp white appearance that helps the pilot pick out the surface quickly on a dark night.