Many people rely on life in the form of climate cycles, such as farmers, fishermen, traders, and so on. This resulted in the emergence of a lot of pressure from various groups of people who needed accurate information on climate information and created various ways to carry out weather forecasts. Weather forecasts are examples of problems that often have unclear or obscure answers. Fuzzy Logic is a technique to solve this problem, so the technique used is The Mamdani as its application in the weather forecast system. Analyzing the results of weather forecasts that occur in Indonesia requires a system to know the accuracy of the data generated, so it is necessary to create a system for forecasting weather based on parameters that are inputted using the Fuzzy The Mamdani technique so that weather forecasts can be more accurate and efficient. This study predicts the weather using fuzzy The Mamdani logic techniques using the Fuzzy and Matlab toolbox as a determinant of an estimate of the weather cycle that is prioritized to be determined, namely the degree of membership functions and the rules used. Fuzzy logic with The Mamdani technique is very good to use as a weather forecast because it has an accuracy level of above 60%. Therefore, the more variables that are used as input, the better (accurate) output will be.