Why are Hindu gods portrayed blue in colour?

Because in ancient civilisation (with the exception of Egyptian) people cannot tell between Dark, Blue and Green. Krishna was described as "Nila" which is the word for both dark and blue. read more

The colour blue depicting the ancient Gods of the Hindu Mythology like Ram, Krishna and Lord Shiva, seem a way to divert the minds of people from connecting any particular "colour" to them, which might happen to discriminate them. read more

It is a fixed, cold colour encouraging meditation and rest oriented towards God. In Tibetan Buddhism blue is the colour of transcendental wisdom and vacuity which opens the door to freedom. Blue is the colour of Yang. There may be another secular reason for using blue colour instead of black in india. read more

An interesting answer to this question can be found in one of the quotes of Swami Vivekananda, "The God of Infinite Love and the object of Love sublime and infinite are painted blue. Krishna is painted blue, so also Solomon's. It is a natural law that anything sublime and infinite is associated with blue colour. read more