Forecast high temperatures for Mother’s Day show a sharp Bay Area split, with 70s near the coast and bay shoreline and 80s spreading through the North Bay, inland East Bay and South Bay.
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Mother’s Day weekend will feature a classic Bay Area spring temperature split, with cool coastal air and near-summer warmth inland.
San Francisco, the Peninsula and parts of the East Bay shoreline will still be dealing with a lingering marine layer, with temperatures mostly in the 60s Friday and Saturday. But head about 20 to 30 miles inland, and the weather starts to feel a lot more like summer. Walnut Creek, Dublin, San Jose and other warmer inland spots will climb from the 70s on Friday into the 80s Saturday and Sunday.
The split comes from the same tug-of-war that defines Bay Area weather this time of year. Cool ocean water will keep feeding a cooler layer of air into the coast and bay shoreline, while a ridge of high pressure slowly strengthens over the West. That ridge will warm the air mass over most of California through the weekend, but it probably won’t build fast enough or close enough to the coast to fully wipe out the marine layer.
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Low clouds and cooler ocean air should spill into the coast, bay shoreline and some inland valleys Friday and Saturday mornings, then retreat unevenly each afternoon. Forecast models suggest clouds will be most stubborn along the coast, San Francisco, the Peninsula and parts of the East Bay shoreline. Places that clear by late morning will warm quickly, while areas that stay under clouds or marine-cooled air into early afternoon will remain several degrees cooler.
Sunday is the less certain day. By then, the ridge will be stronger and inland temperatures will be warmer, which could weaken the marine layer’s grip and allow warmer air to mix closer to the bay. But it may not be a strong effect. A small change in the strength of the onshore flow could be the difference between a sunnier, warmer Mother’s Day around the bay and another day where low clouds linger into late morning or midday.
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The broader heat peak comes Monday and Tuesday, when inland Bay Area temperatures should push well into the 90s and flirt with record territory in a few spots. Even San Francisco and Oakland will likely get pulled into the warmup, with highs climbing well into the 80s.
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Weekend breakdown
San Francisco: Friday starts gray, especially on the west side, before afternoon sun returns. Highs will range from the upper 50s near Ocean Beach to the upper 60s downtown and in the Mission, with west winds at 10 to 20 mph. Saturday looks sunnier and a bit warmer, with highs mainly in the 60s and a few low 70s popping up. Mother’s Day is trickier. San Francisco should stay partly cloudy, with highs in the low 60s to low 70s. The west side of the city should stay cooler, while downtown, SoMa, the Mission and Potrero Hill have the best shot at the 70s if the marine layer backs off enough. Clouds will return each night, with temperatures in the low to mid-50s.
North Bay: This is where the weekend warmup shows up fastest. Friday brings patchy morning fog in some interior valleys, then sunshine and a clear step toward warmer weather. Santa Rosa and the warmer Wine Country valleys will climb well into the 80s through the weekend, with some spots nearing 90 by Mother’s Day. Napa, San Rafael and Novato will run a bit milder, generally landing in the upper 70s to low 80s. The coast is a different story. Point Reyes and the Marin shoreline will stay much cooler, with marine air keeping temperatures closer to the 60s and low 70s. Nights should stay relatively comfortable, with cooler valley spots dropping into the upper 40s and low 50s.
East Bay: The shoreline gets the slower version of the warmup, while the interior valleys take a bigger step toward summer. Oakland, Berkeley, Richmond and Hayward will still start with some clouds, then turn milder as afternoon sun breaks through, with highs generally in the upper 60s to mid-70s through the weekend. Fremont and the I-880 corridor should run a little warmer, mostly in the 70s. East of the hills, Walnut Creek, Concord, Dublin, Pleasanton and Livermore will climb from the upper 70s Friday into the low to mid-80s Saturday and Sunday. Antioch and far eastern Contra Costa County will be among the hottest spots, with highs pushing into the mid- to upper 80s by Mother’s Day.
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Pacific Coast and Peninsula: The coast stays tied to the marine layer. Pacifica and Half Moon Bay will hover near the upper 50s and low 60s Friday, then only warm a few degrees through the weekend. Daly City should run a bit milder but remain marine-influenced, with highs mostly in the 60s. The real contrast is farther inland along the Peninsula, where Redwood City and San Mateo could rise into the 80s by Sunday if the marine layer backs off enough. SFO will likely sit between those two air masses, warmer than the coast but cooler than the inland Peninsula. Low clouds and fog will return each night, with overnight temperatures mostly in the upper 40s to mid-50s.
South Bay and Santa Cruz: Friday will be warmer but still fairly mild, with most of the South Bay in the 70s and the warmer southern edges near Morgan Hill and Gilroy closer to 80. Saturday and Sunday bring more sun and a steady warmup. San Jose, Cupertino, Los Gatos, Morgan Hill and Gilroy should climb into the upper 70s and 80s through the weekend, with the warmest spots reaching the mid-80s by Mother’s Day. Santa Cruz will be warm for the coast but still moderated by the ocean, generally in the 70s, with cooler conditions near the immediate shoreline. Overnight lows will stay mostly in the upper 40s to mid-50s.