  We study the distribution of the Frobenius traces on $K3$ surfaces. We
compare experimental data with the predictions made by the Sato--Tate
conjecture, i.e. with the theoretical distributions derived from the theory of
Lie groups assuming equidistribution. Our sample consists of generic $K3$
surfaces, as well as of such having real and complex multiplication. Each time,
the theoretical density and the histogram obtained by counting points match in
the range of visible accuracy. Thus, we report evidence for the Sato-Tate
conjecture for the surfaces considered.
