Monterey sits at the southern end of Monterey Bay, about 120 miles from San Francisco, and its weather can feel like a different climate. The city is one of the most scenic small towns on the California coast, and its weather is part of the appeal. Summers are milder than San Francisco's and warmer than the exposed Marin coast, with a cool ocean climate that is gentler than San Francisco's summer fog. The bay itself shapes conditions along its whole northern curve of coastline. To see how much the measuring spot matters, compare recent Monterey shoreline and offshore water temperatures with the monthly Bay and ocean averages.
The Monterey Bay Effect
Monterey Bay is a large horseshoe of water roughly 25 miles across at its mouth and 13 miles deep, opening to the northwest. The bay's orientation means that the dominant northwest winds and northwest swells hit the outer coast of the Monterey Peninsula rather than the inner bay facing Santa Cruz. Monterey itself, tucked into the southern curve of the horseshoe, is partially sheltered from the strongest marine flow and the coldest upwelled water.
That shape gives Monterey different conditions from the exposed beaches to its north. In late summer, the water near Monterey runs in the high 50s to around 60°F. It is still cold, but several degrees warmer than the water off Half Moon Bay or Point Reyes. As a result, less fog forms over the inner bay and morning fog tends to burn off by midday. Air temperatures are milder than both the foggy Bay Area coast to the north and the hot inland valleys.
When Does Summer Fog Clear in Monterey?
Summer in Monterey follows the familiar Northern California coastal pattern. Mornings are cool, with fog or low clouds that burn off by late morning, and afternoons warm up before the sea breeze picks up. July and August highs average in the upper 60s at NOAA's Monterey station, warmer than San Francisco's chilly July but cooler than Santa Cruz, just up the bay. The Pacific Grove side of the peninsula, which faces the open ocean, runs a few degrees cooler than downtown Monterey or Carmel.
Fog in Monterey tends to be less persistent than in San Francisco, and it burns off more reliably. San Francisco can sit in fog until 2 or 3 PM when the marine layer pushes hard, while Monterey usually clears by noon or earlier. That makes the city a better bet for summer afternoons outdoors, though early arrivals should plan for a gray, cool morning in any season.
The Carmel Difference
Carmel-by-the-Sea, just south of the Monterey Peninsula, shares Monterey's cool, foggy ocean climate, with summer highs in the upper 60s and its warmest weather in September and October. About 12 miles inland, Carmel Valley averages July highs near 79°F. Our guides to Carmel-by-the-Sea weather and Big Sur weather cover the month-by-month details and the coast farther south.
Fall: The Best Season
September and October are widely considered Monterey's best weather months, because the North Pacific High weakens and the marine layer loses strength. Morning fog becomes less frequent and less persistent, and afternoon highs average near 71°F. That is warm enough for comfortable outdoor dining, whale watching and walks along Cannery Row. The bay is also at its warmest in fall after absorbing summer heat, which makes kayaking and paddleboarding more pleasant.
Fall also brings the peak of humpback whale feeding in Monterey Bay. The bay's underwater canyon, more than 10,000 feet deep offshore, brings cold, nutrient-rich water toward the surface during upwelling. That water feeds huge numbers of krill and anchovies in fall. Whale-watching boats out of Fisherman's Wharf often see several humpbacks on fall trips. The wildlife and the reliable weather together make September and October the busiest visitor season, for good reason.
Winter and the Storm Season
Monterey winters are mild but wet, with about 20 inches of rain a year, most of it from November through March. Winter storms bring the year's biggest surf to the outer coast. The crashing waves at Point Lobos and along 17-Mile Drive draw visitors looking for wild Pacific weather. The inner bay stays calmer, and whale watching continues through winter as gray whales migrate past from December through March.
January highs average around 60°F, cool but rarely cold, and freezing is almost unheard of at sea level. Mild temperatures, smaller crowds and dramatic storm light make winter in Monterey an appealing time to visit for travelers who care less about beach weather. The aquarium, Cannery Row and the coastal trails are at their quietest, and sea otters, harbor seals and sea lions are as active as in any season. From October to early February, monarch butterflies spend the winter in nearby Pacific Grove, as our guide to when the monarchs fly explains.
