Weather for San Mateo Coast State Beaches, CA - San Mateo Coast State Beaches, CA Weather, Current Weather in San Mateo Coast State Beaches, CA. Local weather report for San Mateo Coast State Beaches, CA, Local San Mateo Coast State Beaches, CA weather. Forecast for San Mateo Coast State Beaches, California, San Mateo Coast State Beaches, CA weather forecast. Find your local San Mateo Coast State Beaches weather forecast. San Mateo Coast State Beaches, CA weather conditions.