Bay Area is dodging extreme heat. Here's what to expect over the holiday

San Francisco Chronicle​

20 hours ago

It's the Fourth of July and much like it was in 1776 in Philadelphia, the weather across most of the country is pretty forgettable. No record heat, no major storms, and a quiet Atlantic hurricane season,unlike the more active Eastern Pacific. But as usual, the Bay Area isn't playing along with the national script.
We've got the usual grab bag of microclimates on display today. A stubborn upper-level pattern is keeping the coast and hills locked in a cooler, cloudier setup through the holiday weekend, while inland areas will start to feel a little more summer-like, though not exactly scorching like last July 4th. In fact, parts of the Tri-Valley and Santa Clara Valley may struggle to crack 80 degrees today. If that holds, it would be the coolest July 4th in the interior East Bay since 2018.
In San Francisco, Oakland and down the Peninsula, highs will sit comfortably in the 60s and low 70s, which is technically below average, but not exactly a shock given the recent run of gray, breezy days. Winds will pick up again in the afternoon, with some of the stronger gusts through the Golden Gate, possibly dragging in some low clouds later. And while some low clouds may try to sneak back into San Francisco by fireworks time, most other fireworks shows across the region should go off without much weather interference.
Illegal fireworks unfortunately cause a huge number of spot fires around the Bay Area each Fourth of July, and strong winds across the interior East Bay increase the risk of fire spreading – particularly east of Mt. Diablo where relative humidity levels will be the lowest.
After Friday, the Bay Area will stay on the fringe of the larger weather systems, far enough away to avoid any extremes. A fairly steady pattern will continue through the weekend, with little day-to-day change.
But early next week, a large ridge of high pressure will build in to our south, bringing the West Coast its first widespread heat wave of the season. How much heat actually reaches the coast will depend on the stubbornness of the marine layer, which won't be quick to give up much ground near the coast.
Independence Day breakdown
San Francisco: The holiday will start cool, gray and blustery. Sunshine will break through by late morning, but don't expect much warmth. Highs will top out in the upper 50s west of 19th Avenue, with low to mid-60s downtown and in the Mission. West winds will blow steadily through the day, with gusts of 30 to 40 mph near the water. So bring layers if you're heading to Fisherman's Wharf for fireworks. Cloud cover will be spotty Friday night, with continued breezy conditions and overnight lows in the 50s.
North Bay: The holiday will bring plenty of sunshine to the North Bay, though it'll stay on the cool side near the coast. Winds from the southwest will be lighter than in the city, mostly 10 to 20 mph with occasional higher gusts. Highs will reach the low 70s from Mill Valley through Petaluma and east toward Napa, with Santa Rosa, Fairfield and Vacaville pushing closer to 80. Overnight, patchy clouds will creep back toward the coast, but skies will stay mostly clear inland. Lows will dip into the 50s, with a light breeze sticking around.
East Bay: The holiday will be cool and breezy across the East Bay. Winds will peak at 30 to 40 mph in the hills and interior gaps, where fire weather concerns are highest. Highs will reach the upper 60s to near 70 from Richmond to Hayward, with mid- to upper 70s in the Tri-Valley. Skies stay mostly clear for evening fireworks, with patchy clouds near the water overnight. Lows will dip into the 50s with continued breezy conditions.
Pacific Coast and Peninsula: The coast stays cool and cloudy much of the day. Partial clearing will arrive late morning in Daly City and Pacifica, and a bit later for Half Moon Bay, with highs in the upper 50s. West winds will gust 15 to 25 mph. The Peninsula will see earlier sun, but stay cool, in the upper 60s in South San Francisco and mid-70s in Redwood City. Gusts could hit 40 mph near the San Bruno Gap. It will be partly cloudy and breezy overnight, with lows in the 50s.
South Bay and Santa Cruz: Despite being shielded against some of the strongest winds, the South Bay will remain cool, with highs in the low to mid-70s in Santa Clara and San Jose with northwest wind at 10 to 20 mph. Santa Cruz might have some of the better weather for the holiday, with mostly sunny skies, temperatures in the mid-70s and not as windy. It should be pleasant in the Santa Cruz Mountains as well. Mostly clear overnight with breezy winds continuing and lows in the 50s.