No one knows for sure. He was a speaker of Aramaic, he was a middle eastern person, he was Jewish. He could have had a skin tone anywhere from dark skinned to light skinned. He wasn't a European, but a lot of us have grown up seeing pictures made by Europeans that depicted him as Northern European looking, with pale skin and light colored hair, but that's only how they imagined he would look. :)
Actually, we of the human race are all the same color. Some shade of brown. Even so-called "white" people are a shade of brown but a light shade. So how we appear has only to do with how much melanin pigment we have in our skin. So the answer is that Jesus was some shade of brown. His characteristics such as skin tone are not determined by classic genetics due to how he came to us so exactly what shade, we don't know.
He was a middle eastern jew so he was hebrew and probably was a shade of medium brown or medium olive. Look at pics of modern Jordanian men or Saudi men or Northern Egyptian men and thats a pretty good approximation. Skin shades vary but in general they are a medium to light brown. In Biblical days there wouldnt have been all the centuries of european genetic influence so you can assume Christ was probably a shade or two darker than many middle eastern men today.