When someone is cooking dinner, they may be making a warm meal because it might be cold outside. A warm meal might include soup. Soup and salad go well together especially for lunch. Some people might think that soup is warm and salads are cold, so they don’t go well together. However, they are both light.
Also, some people like to eat a contrast of things at their meals. They don’t want all warm food or all cold food. They would prefer a combination of things. In this case, eating salads at a warm meal would be a good idea for this person. Therefore, many meals that contain warm entrees also have a cold salad to go along with it.