To answer this question, it is important to bear in mind two things: 1) The basic scientific principle that color is made up of reflected light that our eyes have the ability to sense, and 2) What God, himself, said about light in Genesis 1:1,3 and 4: “In the beginning God created the heavens and the earth. And God said, “Let there be light,” and there was light. God saw that the light was good.”
Since God is the creator of light (and of color as well) and has proclaimed that it is good, meaning that He was completely happy with what He had made, the wonderful answer to the question of God’s favorite color is: ALL of THEM, plus many, many more that we are not yet aware of.
“Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning” (James 1:17).