Figure 3 Upper Awash basin mean rainfall since 1991 to 2015
Midland area stations (Sebata, Kimoye, and Ginchi, Asgori) revealed seasonal decrease with precipitation except Asgori is increasing in the Birraa season. So, it is possible to say all stations resulted in a decreasing trend of seasonal precipitation in 25 years of study time series. These stations increased with maximum temperature at Kimoye and Asgori stations while decreasing trend resulted from Sebata and Ginchi stations. The annual and seasonal precipitation trend of Sebata station is significantly increasing. Moreover, except Bona season of Kimoye andGanna season of Asgori, annual and seasonal trends of temperature significantly increase at 0.1 critical value. But Ginchi and Sebata stations are insignificantly decreased trend with maximum temperature.
Precipitation of Highland area stations (Addis Ababa, Sendafa, Ejere, and Addis Alem) exhibited a decreasing trend annually and inArfaasaa seasons except Sendafa station got an increasing trend. Addis Alem decreased Annually at a 95% significance level while other stations are statistically insignificant. During Ganna season, Addis Alem and Addis Ababa stations increased insignificantly while Sendafa station significantly increased. Contrarily, Ejere stations significantly decreased at 0.05 critical value. Highland stations exhibited an annually decreasing trend except for Sendafa station.