During almost fifty years, fade duration distribution (FDD) of random signals has been an open research topic. However, for Weibull fading channels, closed form solutions are still unknown. Minimum duration outage (MDO) definition is decisive to complement the traditional outage concept and it has been reported, up to now, only for Log-normal shadowing, Rayleigh fading and Nakagami fading. In this paper, FDD and MDO in Weibull channels are studied. By utilizing the relation between Weibull distribution and Rayleigh distribution, analytical results are derived for FDD as well as the performance measures under MDO principle such as frequency of outage, average duration of outage, and probability of outage. Numerical results are presented to illustrate the analytical results.