I've always thought of lightning as being either bright white or yellow in color. However, in the summer I've also seen lightning appear red as so called "heat lightning". What I'm wondering is what colors can lighting be and what causes the different colors. A couple of general answers I've come across on other forums are:
Color depends on what is in the atmosphere that the light is traveling through
Color is due to the temperature of the lightning
but none of the explanations went into detail of what would cause any individual color.