  We discuss several general aspects of the free energy of the standard model
at high temperatures. In particular the Clausius-Clapeyron equation is shown to
yield a relation between the latent heat and the jump in the order parameter.
The free energy is calculated as function of temperature in resummed
perturbation theory to two-loop order. A new resummation procedure is proposed
in which the symmetric phase and the Higgs phase are treated differently. A
quantitative description of the phase transition is achieved for Higgs masses
below $\sim 70$ GeV. The results are found to be in agreement with recent
numerical simulations on large lattices. The phase transition provides no
evidence for strong non-perturbative effects in the symmetric phase.
