Common monkey flower. But in the front country of Santa Barbara this is actually uncommon, perhaps non-existent, with the bush monkey flower being more frequent.
This species lives in streambeds. There is another yellow monkeyflower which is occasional on dry hillsides (and is far more likely to be seen in the front country.
Formerly this genus was placed in the Scrophulariaceae (figwort) family.
I have observed this blooming in June (and not blooming in December) in Manzana Creek but I have not seen it often enough to get a good handle on its flowering times.