San Ramon, CA 94582 Weather

: New UPDATE, MARINE:

Key messages

Updated at 1213 PM PDT Fri Oct 30 2026

- Minor to moderate coastal flooding at high tide for Bayshore and Pacific Coast locations through the weekend

- Seasonal to slightly below seasonal temperatures through the extended forecast

- Potential for rain Saturday and again next week

Update

Issued at 913 PM PDT Fri Oct 30 2026

Weather item of note during the evening hours has been ongoing shower activity over the Southern Diablo Range. Shortly after peak heating of the day cells began to pop over the interior mts of the Central Coast. Instability, daytime heating, and some topographic enhancement led to a few showers. As these showers drifted eastward into the Central Valley they tapped into more instability, which led to showers becoming thunderstorms. Will keep KMUX in precip early tonight as it is still tracking the diminishing cells drifting eastward. Rainfall amounts were generally light with the Santa Rita Peak RAWS tipping .06".

Elsewhere, pretty quiet weather this evening with mid-high level clouds drifting overhead.

Next up will be fine tuning the Halloween forecast.

MM

Short term

Issued at 1213 PM PDT Fri Oct 30 2026 (This evening through Sunday)

There remains a slight chance to chance for rain showers across the Central Coast (mainly across interior Monterey County and San Benito County) through this evening. There is also a 5-10% probability of thunderstorms this afternoon and early evening across the mountains of San Benito County, however probabilities remain low at this time. The primary hazards with any isolated thunderstorms that do develop will be lightning, localized moderate/heavy downpours, and gusty/erratic winds.

Tonight, mostly dry conditions are forecast to persist as the cold front pushes into northern California and weakens as at approaches the Bay Area. This feature will bring chances for rain across the Bay Area by Saturday afternoon and into early Sunday morning. Meanwhile, chances for precipitation across the Central Coast from remnant moisture aimed toward southern California.

All that said, the NBM Probabilities of reaching greater than 0.25" (15-35%) reamin highest along the highest through tonight across Monterey and San Bentio. Then by Saturday night across Sonoma County and 15-45% across Monterey and San Benito counties Saturday night into Sunday morning.

From previous forecaster: "A combination of high astronomical tides and surge from thermal expansion and low pressure effects brings the risk of minor coastal flooding along the Bayshore at the San Pablo, San Francisco, and Monterey Bays, and the Pacific coast, at high tide today. At the San Francisco tidal gauge, high tide is expected to be 1.9 ft above normal (7.7 ft MLLW) at 2:39 PM today, 1.5 ft above normal (7.3 ft MLLW) at 3:44 PM Saturday, and 1.0 feet above normal (6.8 ft MLLW) at 3:59 PM Sunday, including around 1.5 ft of surge residual." The Coastal Flood Advisory drops off after high tide on Saturday for the Pacific Coast but remains in effect through Sunday for bayshore locations along the San Pablo, San Francisco, and Monterey Bays.

Long term

Issued at 1213 PM PDT Fri Oct 30 2026 (Sunday night through next Thursday)

Weak ridging builds in from the eastern Pacific Sunday and into Monday in wake of the exiting trough. This will result clearing of clouds regionwide and dry weather conditions Sunday afternoon through Monday afternoon along with a slight warming trend. However, temperatures will generally remain a few degrees below normal.

Tuesday and beyond, there is still a great amount of uncertainty with the forecast. The current forecast indicates a slight chance of rain/rain showers on Tuesday as a trough or cut-off low approaches the Bay Area and Central Coast. That said, the Climate Prediction Center's 6-10 Day Outlook our region in the 33-40% for greater than normal precipitation.

Aviation

(00Z TAFS) Issued at 450 PM PDT Fri Oct 30 2026

VFR prevails with light rain chances likely in the following TAF issuance (after 06Z) for coastal sites. A mix of high to mid-level clouds persist through the day, which gradually lower towards the end of the TAF cycle. Greater chance for borderline MVFR-VFR ceilings at the Monterey Bay terminals tonight. Onshore breezes around 10-15 kt become light south to southwesterly through the overnight hours, and increase again Saturday.

Vicinity of SFO: VFR. Moderate westerly breezes gradually ease before increasing again Saturday morning. Light rain showers may develop as early as Saturday evening around 7-8 PM PDT (02-03Z), though chances increase after 11 PM PDT (06Z). Lower cloud bases are anticipated with the increasing chances of rain, but are expected to remain VFR or borderline VFR-MVFR.

SFO Bridge Approach: Similar to SFO.

Monterey Bay Terminals: VFR with brief periods of MVFR-VFR ceilings continue through the afternoon. Onshore winds become gentle southerly breezes overnight. Low confidence on light drizzle occuring overnight. Westerly winds around 8-10 kt increase again by late Saturday morning.

Marine

(Tonight through next Thursday) Issued at 913 PM PDT Fri Oct 30 2026

Gentle to fresh northerly breezes prevail over the coastal waters as a weak cold front approaches from the north. These conditions will persist with moderate seas into early next week. Mid-week, wind driven seas build to rough across the outer waters. A long period southwesterly swell persists through the weekend and combines with a long period northwest swell early next week.

Watches, warnings and advisories

CA: Coastal Flood Advisory until 6 PM PDT Sunday for CAZ006-506-508- 529-530.

Coastal Flood Advisory until 6 PM PDT Saturday for CAZ505-509.

PZ: None.