What is the average height and weight of a thirteen year old?

5' 2" and 100 pounds: Very few teens are at the "average" height and "average" weight numbers. Every healthy teen is likely above or below the "average" numbers. But if one does the math and calculates the mean height and mean weight for a large group of 13 year-old kids, the answers will be about 5' 2" and 100 pounds. At age 13 years, the girls' average results will still be slightly taller and heavier than the boys.