While discussions may simplify climate change impacts to increased temperature and more extremes in precipitation, scientific literature has long pointed to increased variability. Temporal changes to average temperatures or shifts in major events, such as the timing of precipitation or the quantity of precipitation coupled with varying temperatures, can have major impacts across both terrestrial and aquatic systems. Vernal pools in the mediterranean and semi-arid climates of southern California depend on winter and early spring precipitation for inundation of pools. Well-timed inundation not only starts the life cycle of the many flora and fauna contained within these aquatic ecosystems, including endangered species, but also provides important habitat for listed and common terrestrial species. Temporal variation in precipitation patterns, or otherwise unseasonal precipitation, can have dramatic impacts on vernal pools, such as changes in the development and timing of when vernal pools become inundated, increased water temperatures, altered water chemistry properties, and increased evaporation. These changes can have negative impacts on the species that depend on these vernal pool systems. The consequences will be very site, context, and species-specific and highly dependent on the ability of the species to adapt to the varying conditions over time.