Optimal timing of reproduction is critical to ensure adequate conditions for raising young. However, factors influencing timing of reproduction may differ between sexes. Harsh seasonal environments offer unique opportunities to link timing with resource availability and strategies of the sexes. The Arizona gray squirrel (Sciurus arizonensis) inhabits arid forests in which precipitation is highly seasonal and exceptionally variable; however, no data are available on diet or reproduction. We investigated annual variation in foraging and reproductive habits of Arizona gray squirrels to assess responses to extreme seasonality. We found that Arizona gray squirrels have a diverse diet, with consumption of major food items shifting between years. Reproduction also varies between years. Reproductive output was greater in 2008, with more females successfully reproducing and males remaining in reproductive condition for extended periods. Males shifted timing of reproductive behaviors in response to female receptivity, which tracked food availability. This shift likely reflects variation in food production due to precipitation, because rainfall varied greatly, with most years prior to and during our study recording below-average rainfall. With drought conditions and extreme rainfall events predicted to increase with climate change, understanding the relationship between climatic events, phenology of food production, and impacts on reproduction is critical when attempting to manage and conserve species.