This paper examines the predictability properties of barotropic and baroclinic geostropic turbulence. By geostropic turbulence I mean rapidly rotating, stably stratified flow with many degrees of freedom, dominated to a greater or lesser extent by nonlinearity. Predictability here is concerned with the rate of divergence, measured by spectra of energy in the difference field, of two initially similar fields. In particular the paper examines the effects of a mean gradient of potential vorticity (the beta effect) and the effects of baroclinic instability on flow predictability. In barotropic (i.e., two‐dimensional) turbulence, beta increases predictability by slowing nonlinear energy transfer between scales. Two layer flow is not so affected, because beta increases the range of wavenumbers over which significant energy transfer occurs due to the modification of the linear stability properties of the system. In two layer flow baroclinic and barotropic effects each account for about half of the loss of predictability.