Spatio-temporal Dynamics of Rainfall and Temperature in Addis Ababa: Variability, Trends, and Extremes

Understanding the temporal and spatial variability of rainfall and temperature is essential for climate adaptation and urban planning in rapidly growing cities. This study examines the monthly, seasonal, and annual patterns of rainfall and temperature in Addis Ababa, Ethiopia, over the period 1981-2022, using high-resolution 4 km gridded climate datasets. Trends were assessed using Modified Mann-Kendall (MMK) and Sen’s slope estimators, while inter-annual variability was quantified using the Standardized Anomaly Index (SAI) and coefficient of variation (CV). Extreme temperature events were evaluated based on the 90th percentile for heat stress and the 10th percentile for cold stress. The analysis shows that Addis Ababa experiences its highest rainfall during the Kiremt season, particularly in the northern and northeastern parts, while the Belg season contributes moderate rainfall, and Bega remains the driest season. Mean monthly temperatures peak between March and May, whereas cooler conditions prevail from July through January. Spatially, southern, central, and eastern areas are consistently warmer, while northern and northwestern sectors are cooler. Trend analyses indicate no statistically significant changes in rainfall, although a slight decline in Belg and a modest increase in Kiremt are observed. Conversely, both maximum (Tmax) and minimum (Tmin) temperatures show significant increasing trends across all seasons and annually, with Tmax rising most rapidly during Belg (0.085°C yr<sup>-1</sup>) and Tmin increasing sharply in Bega (0.065°C yr<sup>-1</sup>). SAI and CV analyses highlight high inter-annual and seasonal variability in rainfall, whereas temperature variability remains relatively low, underscoring rainfall as the dominant driver of climate variability. Extreme temperature assessment reveals that heat stress events are concentrated in Belg, while cold stress is most pronounced during Bega. These findings provide a comprehensive overview of rainfall and temperature dynamics, trends, and extremes in Addis Ababa, offering essential insights for climate adaptation, urban planning, and resource management. The observed warming trends, combined with spatial and seasonal variability, emphasize the need for targeted monitoring and adaptive strategies to mitigate climate-related risks in the city.