I had the impression that the lightning colors we see at the pictures were depended on the camera settings. It is true that by adjusting the color balance during the shooting or post processing we can manipulate or totally alter the colors and tones on any picture. At this particular image I noticed something peculiar. This is a stack of approximately 10 photos taken with the exact same settings and color balance (daylight) during an intense thunderstorm at Kos island, Greece. The colors of the lightnings are exaggerated at post processing but are actually the real colors. Half of the lightnings produced a blue glare and the other half were red. According to ask.com
Lighting takes on a range of colors depending on the conditions that are in the clouds and in the air. The blue lightning shows the presence of hail while the red one indicates the presence of rain.
Most often it will appear white as it travels through the air, but can appear orange or red when off in the distance. This is due to particles of dust, haze, and moisture in the air that diffuses the color it appears to be.
As this was a fast approaching thunderstorm, perhaps the most distant lightnings emitted a reddish color and as the storm approached turned to blue or maybe this picture indicates a large area with hail and rain alternations.
Camera Model Canon EOS 550D, Shooting Date/Time 14/11/2013 20:55 – aprox. 21:07, Author Chris Kotsiopoulos, 20 sec x aprox. 10 shots (out of 42), Aperture Value 5.6, ISO 100, Lens Canon EF28mm f/1.8 USM, Focal Length 28.0 mm