South San Francisco, CA Weather

Key Messages

Updated at 226 PM PDT Mon Oct 26 2026

- Coastal flooding at high tide by Bayshore and Pacific Coast locations through the week. Worst flooding along bayshore Marin County.

- Seasonally cool conditions this week

- Light rain possible Friday into the weekend

Short Term

Issued at 226 PM PDT Mon Oct 26 2026 (This evening through Tuesday night)

Seasonal to seasonally cool temperatures continue through the upcoming week as upper level troughing lingers over the West Coast. Overnight temperatures will also be on the cooler side with morning lows dropping into the 40s to upper 30s across the region. In the Short Term, expect more classic fall weather to continue with gustier onshore winds in the afternoon/evening. Stronger winds peak between 25 to 30 mph along the coast and across mountain gaps/passes (Altamont Pass, Salinas Valley, San Bruno Gap - to name a few). Winds ease overnight but expect another round of gusty onshore winds during the afternoon/evening on Tuesday.

The main hazard Monday/Tuesday continues to be the threat for coastal flooding along the San Francisco/San Pablo Bay shorelines and along the Pacific Coast. This coastal flood event is brought to you by a combination of the full moon (10/26) and thermal expansion due to warmer ocean temperatures on top of our typical tidal pattern. High tides peak today and tomorrow with up to 2.1 ft of inundation above ground level expected. The strongest impacts will be felt along low-lying portions of bayshore Marin County where numerous flooding reports have already been received. If you live in a low-lying area prone to flooding along the bay or Pacific Coast, make sure to have all flood preparations in place before high tide tomorrow (12:15 PM). If you encounter a flooded road, turn around don't drown. You don't know how deep flood waters are, how fast a current may be, or if the road is structurally sound beneath the water. Coastal flooding is set to peak on Tuesday with tidal heights dropping throughout the long term (for more in depth discussion see the Long Term forecast).

Long Term

Issued at 226 PM PDT Mon Oct 26 2026 (Wednesday through next Sunday)

Troughing generally persists through the upcoming week with a deeper upper level low arriving Friday into the weekend. Seasonal to seasonally cool temperatures continue through the extended forecast but expect temperatures to drop another couple of degrees Friday into the weekend. Diurnally gusty winds continue for favored locations this week with stronger gusts during the afternoon/evening along the coast and across mountain gaps/passes. High temperatures Wednesday and Thursday will be in the mid to upper 60s across the interior while coastal areas linger in the upper 50s to low 60s. Friday we see the promised further cooldown with interior lows dropping into the low 60s and most coastal areas lingering in the mid to upper 50s. Cooler temperatures remain in place through the end of the weekend. Expect overnight cloud cover to return by midweek with cloudy skies becoming more predominant Thursday into the weekend as the deeper trough arrives. Light rain remains possible Friday into the weekend but, fortunately, the bulk of the rain has shifted southwards towards Southern California. That's not to say we will be completely dry this weekend. Expect drizzly conditions across the Bay Area Saturday into Sunday with light rain possible overnight heading into Sunday. Light rain is expected across the Central Coast but totals should be fairly light across urban areas (around a tenth of an inch). For the higher elevations of the Santa Lucia Range and the Gabilan Range, light rain amounting to a couple tenths of an inch is possible. All together, the classic fall weather should lend itself a ghostly ambiance for anyone partaking in any haunted/spooktacular activities this weekend.

Coastal flooding concerns continue across Bayshore locations within the San Pablo, San Francisco, and Monterey Bays and the Pacific coastal regions through at least Thursday. While tidal heights peak Tuesday, heights will remain elevated through late week. At the San Francisco tidal gauge, high tide is expected to be 1.9 ft above normal (7.7 ft MLLW) at 12:56 PM Wednesday 10/28, 1.7 ft above normal (7.5 ft MLLW) at 01:43 PM Thursday 10/29, 1.4 ft above normal (7.2 ft MLLW) at 2:39 PM on Friday 10/30, and 1.0 feet above normal (6.8 ft MLLW) at 3:44 PM on Saturday 10/31, including around 1.0 ft of surge residual partially attributed to impacts from El Nino. Currently, tidal heights continue to run above the forecast with the forecast heights for Monday/Tuesday being increased. If this trend continues into mid to late week we may see coastal flooding concerns extended Friday into the weekend (necessitating the extension of the product). Expect the worst flooding to continue in low-lying bayshore locations of Marin County.

Aviation

(18Z TAFS) Issued at 128 PM PDT Mon Oct 26 2026

Satellite imagery shows clear skies for much of the region with some stratocu clouds lingering around the North Bay. Sites are still reporting VFR conditions and this should hold through the evening. There isn't much change in the pattern today, so expect to see similar conditions tonight as we did last night. A mix of VFR and MVFR ceilings are forecast, the question being if we get a round of IFR or LIFR conditions again. Confidence is high for the mix of VFR and MVRF cigs, but low to moderate for KSTS staying VFR tonight.

Vicinity of SFO...Winds will remain breezy through the afternoon and evening hours with gusts peaking around 20-25kt. Winds should gradually ease after sunset, with the forecast challenge becoming ceiling heights. Like last night, models flirt MVFR cigs around the vicinity of SFO. Given there isn't much of a pattern change, expect the forecast to be on repeat tonight. If that is the case, we may see BKN MVFR cigs from 12-16Z VFR conditions returning after that. Another breezy afternoon and evening is expected for Tuesday with wind gusts up to 20-25kt possible.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR conditions should prevail for the afternoon and evening hours and be accompanied with breezy onshore winds. Gusts look to be peak between 18-22kt around the Bay, before decreasing late in the evening. Much like the discussions above, models show MVFR cigs flirting around the Bay. Kept the trend of them arriving early Tuesday morning clearing out around or just after sunrise.