This permanent water flow, rare in the Santa Monica Mountains, is critical for the maintenance of a number of rare species. Smaller tributaries of Cold Creek flow out of the core area of Stunt Ranch Reserve, providing a well-developed corridor of riparian habitat. This average value, however, obscures the extreme variability of rainfall between drought and flood years. In addition, rain in this region may fall with remarkable intensity for brief periods. In general, however, temperature conditions are moderated by the close proximity of the Pacific Ocean.
Frosts occur occasionally in winter.
The core reserve area of Stunt Ranch encompasses a mosaic of chaparral, live-oak woodland, riparian, and grassland communities. Riparian communities are particularly well developed, both on small tributary streams and along Cold Creek. Both native and secondary grasslands are present on Stunt Ranch. A rare member of the sunflower family, Pentachaeta lyonii , a state-listed endangered species, is also present. Overall, more than 300 species of vascular plants have been reported for the Cold Creek watershed.