According to American Topsoil, a cubic yard of topsoil weighs, on average, about 2,000 pounds. This weight, however, can change based on the moisture content of the soil.
American Topsoil asserts that the weather can have a large effect upon the soil, either increasing or decreasing the weight by 15 percent or more. On hot, dry summer days, the heat can dry out the soil, causing the weight of a cubic yard to fall by 300 pounds or more. However, on wet, rainy days, the weight of all the extra water can raise the overall weight to well over 2,000 pounds.