The duration of a construction project is not only a key element for taking a new order, but also a strict yardstick to
determine a certain project successful or not. While construction project is full of uncertainty and contains many risk factors, however, the current schedule planning work relies on traditional deterministic scheduling methods. Among the all construction processes, the structural work is basically an outdoor work and most of the activities are proceeded out-air, that no matter how the schedule plan has been established accurately, an actual project is mostly affected by the weather condition, beyond anyones control. Thus, the weather condition and the work cycle time for a unit section among many risks, have been chosen as main two factors to calculate the duration of structural work. The aim of this research is to present a probabilistic model to forecast the duration of structural work in high-rise building construction considering weather elements.