The California Current is the primary factor contributing to the mild climates in coastal California.

This cold ocean current flows southward along California's coast, keeping temperatures cooler in the summer and warmer in the winter. The cool current helps moderate the region's climate, preventing extreme temperature fluctuations, which is characteristic of the Mediterranean climate. Coastal areas experience mild, pleasant weather year-round, with dry summers and wet winters. The California Current plays a major role in keeping the coast from getting too hot or too cold, making it an ideal climate for agriculture, tourism, and outdoor activities.