A comprehensive study of the magnetic properties of non-interacting single-domain particles with cubic magnetocrystalline anisotropy is presented. These numerical calculations extend the zero-temperature predictions of Joffe and Heuberger and enable the effects of thermally activated magnetization reversal on the hysteresis loop at finite temperatures to be determined. Variations in particle size distribution are also considered. Calculations indicate a reduction in the intrinsic coercivity as the mean particle diameter is reduced and an increase in coercivity for small particle diameter systems as the standard deviation of the size distribution is increased.