The paper provides a comprehensive performance evaluation of an autocorrelation based frequency estimator in different fading channels. The efficiency of the estimator in terms of exact CRB and asymptotic CRB is investigated under different fading conditions - slow fading, fast fading, Rayleigh fading and Rician fading. The approximate CRB, which provides an insight to the fading process, has been evaluated via a frequency domain technique. The optimal autocorrelation lag value suitable for frequency estimation under different fading conditions is also determined and closed form expressions for the estimate variance are provided. Simulations are shown to verify the theoretical analysis.