Climate change has negative impacts on construction. Climatic conditions complicate job management and cause problems in the completion of the work with the foreseen time and cost. Especially the changes seen in rainfall such as snow and rain have negative effects on the construction sector. In this context, in this study, the time and cost planned before construction and the time and cost realized after the application in a construction in Istanbul are compared. This study put forward a formula that shows the impact of climate change on construction costs. Thanks to this formula; will be added as a coefficient to the cost of climate change, and the extent to which climate change will harm the project will be calculated. Formula not only in Turkey, the international usable.