The main objective of this training manual is to develop step-by-step instructional materials for agriculture extension agents on how to integrate and utilize long-term climate data in a typical and commonly used crop model such as the Agricultural Production Systems Simulator (APSIM) and identify a Context-Based Climate Adaptation Option (CBCAO), in three unique circumstances. Firstly, taking Morocco as an example, the manual demonstrates yield gap evolution under climate change in a rainfed agroecosystem and the relative effects of two Intergovernmental Panel on Climate Change (IPCC) scenarios, Representative Concentration Pathways (RCPs) 8.5 and 4.5. Additionally, supplementary irrigation is applied as a key climate adaptation measure in a location suffering from increasing droughts to augment water supply in arid weather conditions. Secondly, taking Iraq as an example, the manual demonstrates changes in water productivity and yield dynamics in an arid but irrigated agroecosystem to show how judicious irrigation techniques, as opposed to conventional irrigation as a climate adaptation measure, can enhance water productivity while also maintaining and possibly maximizing yield. Thirdly, taking Jordan as an example of a semi-arid agroecosystem, the manual demonstrates crop diversification and defines optimum cropping patterns (selection of alternate resilient crops) as a key climate adaptation measure and assesses impacts on soil carbon sequestration.