This accounts for the grey at sunset. In the morning, the red at sunrise is caused by the long path the sunlight takes through the atmosphere and indicates no clouds to the east. Generally weather and climate lore must be applied in the environment for which they were developed. For example, in southwestern Alberta, the presence of a Chinook arch usually results in warm and windy conditions. A similar appearing cloud elsewhere will not foretell of this event.
Some weather lore is linked with recurring events which have general applications.
Modern day studies confirm that this is generally a valid prediction. The sun dogs are produced by small ice crystals in the atmosphere. These crystals increase as an air mass becomes wetter. Light strikes the ice crystals and is broken up into its component colors in the way that a prism does. Some of the lore based on animal and plant activities has been severely criticized in the past.