Given that rainfall in Ethiopia is unreliable and unpredictable, with the context of the past tells the future, in this book, we have tried to illustrate the rainfall data analysis to serve the operations in agriculture and water resources management. We believe readers and researchers will have the book valuable for references and for making furtheProf. r research in the topic. The authors would like to have critical assessments from researchers the discipline for further improving the scientific contributions that they are going to make in the subject.