The paper presents the impact of the weather on inland navigation conditions. Each mode of transportation depends on the weather, but inland navigation is the one most affected by it. Inland navigation is strongly dependent on the water level in a river bed, which is a result of weather conditions. In Poland the depth of inland waterways is relatively low, but the biggest consideration is the weather which results in the variability of this level. The variability of hydrotechnical conditions results in problems with planning for transportation. It is widely known that water is one of the most important factors in the hydrotechnical conditions of inland navigation and it is directly correlated with the weather. In this paper the authors present the impact of temperature on the duration of the navigation season on the Border Oder, based on research conducted in the years from 2004 to 2018 and the authors also investigated important changes in the weather conditions during last few years. The results showed that the number of navigable days has dropped significantly over the investigated period as a result of changes in the climate.