||The construction planning is complex because of many uncertainties occurring during the execution process. One of the uncertainties, which clearly affects construction activities, is bad weather conditions. From management perspective, it is worth simulating the construction process regarding to weather factors in order to make it more realistic and effective. In practice, the effect of weather can be included in planning stage based on the historical weather data or typical weather patterns of local areas. However, the weather condition variation is often complex and not always the same as how it used to be. Therefore, in the executing stage, the actual weather forecast on site should be considered, so that the execution plan for the next days will be more realistic. In the research project “Simulation of Outfitting Processes in Shipbuilding and Civil Engineering” (SIMoFIT) by the Bauhaus-University Weimar and the German shipyard company The Flensburgers, a constraint-based simulation approach was developed to improve the construction planning in civil engineering. The constraint-based concept is implemented using discrete-event simulation. Attributes and relations between work steps are described by hard and soft constraints. Thus the practical workflow schedule can be flexibly calculated, where all hard constraints are fulfilled and soft constraints are fulfilled as many as possible. This paper presents a simulation framework to incorporate the impact of weather factors into constraint-based simulation of construction processes, where the weather effects are described as constraints. Besides, a “WEATHER” component is described, which generates weather conditions and decides on the impact of weather on each work step. In this research, the data of 5-day free weather forecast retrieved from internet is utilized, where it is updated every 3 hours everyday. Finally, the non-weather- and weather- related-duration of execution processes are achieved and compared.Describing the impact of weather as constraints is a flexible, useful method to include weather effects into a execution process. Further research will concentrate on developing the “WEATHER” component more deeply, defining and optimizing construction strategies within a time-restricted space, and developing the assigning strategies of workers concerning the impact of weather conditions.