Original: They rarely rise above 24 °C (75 °F) in near-shore southern California, and usually don't get above 17 °C (63 °F) along most of the rest of the coast and outer coastal waters, although El Niño events may warm the waters somewhat.
Simplified: NOAA Tropical Cyclone FAQ Normally, the waters' temperatures don't get above 17 °C (63 °F), although El Nino effects may sometimes warm the waters a little bit.