Analysis of Seasonal and Annual Rainfall Variability and Trends in South Gondar Zone, Ethiopia

<title>Abstract</title> <p>Climate variability and change are among the most critical challenges affecting agriculture and water resources in Ethiopia. This study investigates the climatology, variability, and long-term trends of seasonal (Bega, Belg, and Kiremt) and annual rainfall in the South Gondar Zone, Ethiopia, using rainfall data from meteorological stations for the period 1991–2020. Descriptive statistics, the Coefficient of Variation (CV), the Standardized Anomaly Index (SAI), and trend analysis were applied to assess rainfall characteristics, variability, and temporal trends. The results revealed a highly seasonal rainfall regime with considerable interannual variability across all seasons. SAI analysis identified alternating wet and dry years, indicating substantial temporal fluctuations in rainfall distribution throughout the study period. Kiremt rainfall is the main rainy season in the study area, exhibited pronounced year-to-year variability, whereas the Bega and Belg seasons showed relatively higher variability based on CV values, suggesting greater instability in the dry and short rainy seasons. Trend analysis indicated a weak decreasing trend in Bega rainfall, while Belg, Kiremt, and annual rainfall exhibited increasing tendencies. However, all trends were statistically non-significant at the 95% confidence level, indicating that rainfall variability is more dominant than long-term directional change in the study area. The observed rainfall variability is likely associated with large-scale climate systems that influence seasonal rainfall patterns over Ethiopia. Overall, the study highlights the dominant role of climatic variability in shaping rainfall behavior in the South Gondar Zone, with important implications for climate adaptation, agricultural planning, water resource management, and climate risk reduction. The findings emphasize the need for improved climate monitoring, seasonal rainfall forecasting, and strengthened early warning systems to support effective climate risk management in the region. oo</p>