Areas deeper than 40 feet are rare. The deepest portions are near the mouth. The central and southern portions are less than 12 feet deep except where dredged. Climate of the Area Subtropic Mediterranean temperature Average air temperature is from 54 degrees in January to 70 degrees in August. Rain occurs November through April.
Winds are landward during the day and seaward at night.
Back to top 3. Drainage and Runoff Otay and Sweetwater River watersheds, Paradise and Las Chollas Creeks drain into the southern portion of the bay. Otay and Sweetwater River watersheds were approximately 368 square miles in 1973, Paradise and Las Chollas only 47 square miles. San Diego River drained into the bay until 1857 when the Army Corps of Engineers diverted the flow into Mission Bay via Derby Dike. Pumping of fresh ground water adjacent to the bay Reservoirs built on the various rivers that feed the bay 4.