Water temperature affects all creatures living in the stream, as well as directly influencing water chemistry (see the Conductivity and Dissolved Oxygen sections). Different animals have different preferred temperature ranges; cold water fish such as rainbow trout like water to be less than 16°C, although they can tolerate higher temperatures. Deep, fast-moving, and shaded streams tend to be colder than shallow, slow-moving, and exposed streams.
In San Pablo Creek, water temperature typically ranges between 10 to 20°C, but do not reach 25°C, which can be lethal to fish.