Ask the meteorologist: Why do I see different colors of lightning?

What determines the different colors of lightning? I always made the assumption it had something to do with the different elements present in the path of the lightning bolt itself. — William C. Clancy

Answer: For the typical lightning discharges we see travel from cloud to ground, cloud to cloud, or inside a single cloud, there isn't really a great variety of color that relates to the air it passes through.

The intrinsic color of lightning in almost all of those cases is a white or bright bluish-white similar to most other sparks passing through air.

However, scattering and absorption of shorter wavelengths of light by air molecules, natural aerosols and pollutants can deplete the blue and green components so that by the time the light reaches your eye, it can appear to be more yellow, orange or red.

The particular hue that is seen depends on distance from the lightning channel, and on the concentration and size distribution of particles that the light encounters between the site of the lightning bolt and the eye of the observer.