Rainfall is the most important source of water for crop production in Ethiopia. However, its temporal and spatial variability is leading to serious food shortages and insecurity in the country. This study was aimed at investigating the characteristics of selected agroclimatic variables over the great Rift Valley regions of Ethiopia. Long term (1981–2010) climate data were analyzed for 17 stations selected based on agroecology representation. Selected descriptors for climate variability and the Mann–Kendall trend test were employed. Onset, cessation, length of growing period (LGP), water requirement satisfaction index and dry spell occurrence during the growing period were determined. The results showed low to very high rainfall variability (14–35%), LGP (20–256 days) and dry spell probability (50–100%) during the main season. Significant (P ≤ 0.05) annual and seasonal rainfall trends were observed in some stations. The probability of occurrence of a dry spell during the seasons was found to be a challenge for most of the stations in the mid and low altitude areas of the basins. Consequently, seasonal water deficit was observed in these areas which hampered crop production. Area specific recommendations are thus required based on specific challenges in the study region.

降雨是埃塞俄比亚作物生产最重要的水源。但是，其时空变化导致该国严重的粮食短缺和不安全状况。这项研究旨在调查埃塞俄比亚大裂谷地区某些农业气候变量的特征。根据农业生态学代表性分析了17个站点的长期（1981-2010年）气候数据。选择了气候变异性和Mann-Kendall趋势检验的描述符。确定了生长期的发病，停止，生长期（LGP），需水满意度指数和干旱时期。结果表明，在主要季节，降雨变化率从低到高不等（14-35％），LGP（20-256天）和干旱概率（50-100％）。重大 （P在一些车站，观察≤0.05）年度和季节降水趋势。对于盆地中低海拔地区的大多数气象站来说，在季节中发生干旱的可能性是一个挑战。因此，在这些地区观察到季节性缺水，阻碍了作物的生产。因此，需要根据研究区域的具体挑战，提出针对具体地区的建议。