Kingwell, R.S., Pannell, DJ. and Robinson, S.D., 1993. Tactieal responses to seasonal conditions in whole-farm planning in Western Australia. Agric. Econ., H: 211-226.In dryland agricultural systems, efficient farm management requires a degree of flexibility according to variations in climate from year to year. Tactical adjustments to the mix of farm enterprises can capitalizc on good growing conditions and minimise losses under poor growing conditions. In this paper, a discrete stochastic programming mode! of dryland wheat-sheep farms in Western Australia is used to identify optimal tactical adjustments to c1imate and to calculatc the value of these tactical adjustrncnts. The rnodel, MUDAS, includes nine discrete scason types with a wide range of options for tactical adiustmcnts in each. In the standard modcl, optimal tactical responses increase cxpected net cash surplus by approximately 22% relative to a fixed or inflexible strategy, In most season types, changes to the long term farm strategy arc made on less than 10% of the farm arca, although in some seasons over 25% of the farm can rcquire adjustments to the enterprise scleeted. The benefits of f1exibility arc not evcnly distributed aeross different season types but occur predominantly in the best and worst seasons. The magnitude of bencfits is affected differently by different eommodity priees. Benefits of flexibility arc duc to capitalizing on knowledge about the grcater volatility of profits from cropping than from livestock production. Deterministic models and even stoehastic models which don't include activities for tactical adjustments miss this key feature of the system.Notwithstanding the high variance of world priees for most agricultural commodities (e.g. Hazell et al., 1990), climate is the major source of income Correspondence to: DJ. Pannell,