Background: At the centre of smallholders' adaptation is a need to understand their perceptions on key climatic scenarios so as to glean helpful information for key decision-making processes. In Kenya at the moment, downstream information regarding these circumstances remain scanty, with many smallholders being 'on their own', in spite of the imminent threats from shifting precipitation patterns, rising temperatures, and intensifying droughts. At the sub-national levels, potential impacts of these situations are likely to deepen due to extensive cases of land use transformations, habitat degradation, plummeting water resources capacity and common inter-ethnic conflicts, among other negative externalities. The study examined current climatic situations in Trans-Mara East sub-County, to the south-western part of Kenya, as well as the smallholders' perceptions about the situations, their adaptation levels and constraints thereof. Results: Pearson correlation coefficient, indicated a weak positive association between smallholder's perceptions and either their age, marital status, level of education, or livelihood streams (r ≤ 0.1; p ≥ 0.05, for all), unlike their climatic perceptions and farm sizes which showed a strong positive association (r = 0.430; p ≤ 0.01). Key desired adaptation options, improving crop varieties, livestock feeding techniques and crop diversification, topped their options, with destocking being least desired. Education levels (r = 0.229; p ≤ 0.05) and farm sizes (r = 0.534; p ≤ 0.01) had a positively significant association with adaptive capacity, in addition to a significantly weak, association between their adaptive capacity and both their individual's marital status (r = 0.154; p ≥ 0.05) and diversity of livelihood streams (r = 0.034; p ≥ 0.05). The analysis also showed a weak negative association between their adaptive capacity and age (r = − 0.026; p ≥ 0.05). Amid the key constraints which emerged include high cost of farm inputs, limited access to credit and market uncertainties, among others. Pearson correlation coefficient showed a significantly strong negative association between smallholders' constraints and both (r ≥ − 0.3; p ≤ 0.01) their level of education, and diversity of livelihood streams. A significantly strong positive association (r = 0.280; p ≤ 0.01) was identified between smallholder's age and constraints, while marital status and farm sizes both (r ≤ − 0.01; p ≥ 0.05) revealed weak non-significant negative association with the constraints.