Spatiotemporal trends in temperature and rainfall extremes in central and Northwestern Tigray, Ethiopia

The northern part of Ethiopia is frequently affected by recurrent droughts and erratic rainfall affecting agricultural production and food security. The objective of this study was to analyze the trends and spatiotemporal variability of extreme temperature and rainfall indices in the Central and Northwest zones of Tigray. Long-term climate data were obtained from NASA POWER from 1983 to 2023. Trend analysis was carried out on 21 selected extreme temperature and rainfall indices recommended by the joint CCL/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI). The non-parametric Mann-Kendall trend test and Sen’s slope estimator were employed to determine the trends in temperature and rainfall across the study areas over the past forty years. The findings uncover the extreme temperature and rainfall variability, highlighting a highly significant (p < 0.01) increase in warming indicators and highly significant (p < 0.01) decreasing trend on cooling indicators. The average TXx and TNx increased from 0.02 to 0.025 and 0.013 to 0.016 °C per year, respectively over last forty years across the study areas. The annual rainfall showed non-significant positive trends, with Sen’s slopes ranging from 0.38 to 3.50 mm per year. Trends in heavy (R10mm) and very heavy (R25mm) rainfall events varied spatially, with Sen’s slopes ranging from − 0.02 to 0.09 days per year and 0.01 to 0.15 days year⁻¹, respectively. The current study revealed a significant warming trends characterized by increase in extreme temperature and decreases in cool temperature extremes. Despite its reliance on gridded NASA POWER data, and limited spatial coverage, and requiring observed data for validation, the results provide a baseline evidence for understanding recent climate extremes and may support climate-risk assessment and adaptation planning in the region.