Why is Krishna shown with a blue or dark complexion?
The scriptures describe Krishna as shyam, dark like a rain cloud; in paintings this is shown with shades of blue.
Answer
In the scriptures and in devotional poetry, Shri Krishna's complexion is called "shyam", meaning dark or dusky. He is also called "Ghanashyam", one who is dark like a cloud heavy with rain. Painters and sculptors express this divine colour with shades of blue or deep blue.
Tradition offers several symbolic explanations. The sky and the ocean appear blue because they are vast and boundless, and in the same way the Lord is infinite. A rain cloud brings coolness and life to the scorched earth, just as Krishna brings peace to beings suffering from the heat of worldly troubles. Some saints say that a deep colour absorbs everything into itself, just as the Lord accepts everyone.
These explanations come from the feelings of devotees and from tradition. What matters most is that devotees find joy in meditating on his beautiful dark form.