The rain fed crop production is inherently sensitive to climate change and variability. Climaternchange affects all countries but disproportionately affecting the poorest counties and the poorrnpeople with less capacity to cope with. Accordingly, this research is intended to understand thernlocal climate trend in west shoa zone of oromia region, its impact on rain fed crop production inrndifferent agro- ecologies and how the smallholder farmers adapting their agricultural operationrnto the prevailing climate change and variability. The study also investigates the common weatherrnevents, the role of local indigenous knowledge and institutional coping mechanisms currentlyrnpracticed in the area. The study uses two methods; firstly Monthly time series data onrnprecipitation and temperature of three stations (Bako, Ambo and Holeta) with in the Zone werernanalyzed for temporal monotonic trend using Mann Kendall trend test at 95% significant level.rnSecondly, semi- structure questionnaire based interviews and group discussions were also used.rnThe trend evaluation at the three stations reveals more or less stable trend for precipitationrn(Sample Z-values are 0.29 ,-0.27 and -0.97 for Bako, Ambo and Holeta respectively; where asrnthat of temperature shows significant increase and Z-values are 3.54, 1.84 and 2.78 respectively.rnMoreover the socio-economic data analysis indicates that the weather events occurred with inrnthe research area and their frequency are found to be different from place to place; and thernmajor ones are prolonged drought including late on set/early offset (71.2%), flood/Excessivernmoisture (53.8%), heavy rain (32.6%), frost (20.5%) and strong winds (4.5%). As rain fed croprnproduction is dependent on normal distribution and the timely onset and offset of the rainyrnseason, the occurrence of these events hinder agricultural operations and impose differentrnimpacts. The problem is more serious in mid altitude and lowland areas. The survey indicaternthat total crop loss, reduced yield, reduced seeding area, delayed seeding, delayed maturity andrnincreased crop pest are the major impacts. Smallholder farmers use different adaptationrnstrategies such as taking the loss, crop replacement, diversifying crops, late seeding, growing ofrnearly maturing crop, zero/ minimum tillage and growing tolerant crops. The Farmers also usernlocal knowledge such as traditional early warning and tillage practices to cope with adversernweather events. Though small holder farmers have been undertaking different adaptationrnmeasures; constraint of resources such as efficient technologies, land, labor, savings, credits andrncrop insurance is found to be challenging. Moreover, the available institutional copingrnmechanism fails to warn about rapid events like flood, unexpected heavy rain and its multisectoralrnmanner to give immediate response also need consideration. Even though, the long-termrnchange in mean values of precipitation shows stability, there is considerable seasonal and interannualrnvariability. Moreover, the small variability in precipitation and temperature hasrnsignificant impact on rain fed crop production compounded by other compounding biophysicalrnand socio economic factors. Hence, this study indicates small shocks in weather event can resultrnin significant impact, the need to strengthen adaptation options, importance of resources andrnappropriate and timely information on future climate change so as to alert them to takernappropriate averting actions.rnKey words: Climate change, climate trend, adaptation, impact, coping mechanisms