To favour farmers and adjusting their farming practices, long term weather analyses is essential to determine future directions and making adjustments required to existing systems. The main purpose of this study was thus to analyze the variability and trends of climatic variables (temperature and rainfall) and characteristics of crop growth season in Eastern zone of Tigray region for the period of 1980-2009. Detail investigations were carried out using parametric (Linear regression) and non-parametric tests (Mankendall and Sen's slope estimator). Moreover, homogeneity test was applied using a method developed by Van Belle and Hughes for the general trend analysis. Furthermore, the trend of rainfall end to characterize crop growth season using R-Instat and XLSTAT software. It was found that the general trend of monthly rainfall experienced an overall significant increasing trend. The seasonal rainfall experienced significantly increasing trend during the summer rainy season (June-September) whilst a significant decreasing trend occurred in the short rainy season (February-May). Likewise, the seasonal maximum temperature trends exhibited a significant increasing trend in all seasons whereas the minimum temperature showed inhomogeneous trend across seasons as well as stations. Despite significant increase of rainfall in summer season, the trend of growing season characteristics (onset, cessation, length of growing period and dry spell length) did not change significantly over the study period. However, the variability of rainfall and dry spell length was found to be very large. Hence, crop production in the study area demands appropriate adaptation strategies that considers the erratic nature of the rainfall, the long dry spell length in the season and increasing trends of temperature.

Background: Long term weather analyses are very useful indicators in determining future directions and in making adjustments required to existing systems. And, in order to favor farmers to adjust their farming practices, seasonal climate outlooks are needed. The main purpose of this manuscript was thus to analyze the variability and trends of maximum and minimum temperature, monthly and seasonal rainfall series and characteristics of crop growth season in Eastern zone of Tigray region over the period of 1980–2009.Methods: Detail investigations were carried out using parametric (Linear regression) and nonparametric tests (Mankendall (Mk) and Sen’s slope estimator). Moreover, homogeneity test using a method developed by Van Belle and Hughes was used for general trend analysis. In addition, daily rainfall data to characterize crop growth season were analysed using R-Instat and XLSTAT software for trend analysis.Results: It was found that the general trend of monthly rainfall experienced an overall significant increasing trend. The seasonal rainfall experienced significantly increasing in summer main rainy season, June–September (Kiremt) while significantly decreasing in short rainy season, February– May (Belg). Likewise, the seasonal maximum temperature trends exhibited significant increase in each season while minimum temperature trend had inhomogeneous trend across seasons as well as stations. The trend of growing season characteristics (onset, cessation, LGP and dry spell length did not change significantly over the study period (1980–2009) in all stations. However, the coefficient of variability of LGP was (CV, >15%) and dry spell length was (CV, >25%) inassociation with short nature of LGP (68–85 days had a negative impact on the agricultural activities of the study area during the study period.Conclusions: Despite significant increase of rainfall in summer season, the variability of rainfall and dry spell length was very large. Hence, the study recommends crop production in the study area demands appropriate adaptation strategies that considers the erratic nature of the rainfall, the long dry spell length in the season and increasing trends of temperature.

Understanding the likely impact of climate change on crop growth is very important to identify possible areas of intervention and consider climate-related impacts. This study aimed to investigate the future impact of climate change on the crop growing season in the Tigray region. Five global climate models under two representative concentration paths were projected for future periods using a delta downscaling approach. Results indicate that projections of rainfall showed an increase in annual and summer (Kiremt) rainfall at most stations. However, the Belg rainfall season had a declining trend except under RCP4.5 in a mid-term period that showed positive changes at most stations. On the contrary, projections of maximum and minimum temperatures indicated a continuous increase. In line with the increase in temperatures, the reference evapotranspiration consistently increased at all stations. Cumulatively, late onset and early cessation of rainfall are observed, accompanied by a 5.5–19% reduction in the length of the growing period (LGP), exacerbating the current short LGP in the study area and affecting the proper growth and maturity of major crops. The findings of this study have global implications in that similar areas may be alarmed to get prepared ahead and develop adaptive and sustainable crop production strategies.

To favour farmers and adjusting their farming practices, long term weather analyses is essential to determine future directions and making adjustments required to existing systems. The main purpose of this study was thus to analyze the variability and trends of climatic variables (temperature and rainfall) and characteristics of crop growth season in Eastern zone of Tigray region for the period of 1980–2009. Detail investigations were carried out using parametric (Linear regression) and non-parametric tests (Mankendall and Sen’s slope estimator). Moreover, homogeneity test was applied using a method developed by Van Belle and Hughes for the general trend analysis. Furthermore, the trend of rainfall end to characterize crop growth season using R-Instat and XLSTAT software. It was found that the general trend of monthly rainfall experienced an overall significant increasing trend. The seasonal rainfall experienced significantly increasing trend during the summer rainy season (June–September) whilst a significant decreasing trend occurred in the short rainy season (February–May). Likewise, the seasonal maximum temperature trends exhibited a significant increasing trend in all seasons whereas the minimum temperature showed inhomogeneous trend across seasons as well as stations. Despite significant increase of rainfall in summer season, the trend of growing season characteristics (onset, cessation, length of growing period and dry spell length) did not change significantly over the study period. However, the variability of rainfall and dry spell length was found to be very large. Hence, crop production in the study area demands appropriate adaptation strategies that considers the erratic nature of the rainfall, the long dry spell length in the season and increasing trends of temperature.