Marine Weather and Tide Forecast for Lagunitas-Forest Knolls, CA

SHORT TERM
Issued at 1219 PM PDT Tue Jun 23 2026 (This evening through Wednesday)

The marine layer is sufficiently deep around 1200-1500 ft today with satellite showing steady erosion for the inland valleys. Subtle weak ridging remains in place through Wednesday, helping compress the marine layer into Thursday morning. As low clouds push inland again tonight, slightly less inland spread and an uptick in coastal fog can be expected to accompany the shallower marine layer, with visibility impacts most prevalent for coastal terrain. As such, clouds may burn off earlier in the day on Wednesday for most areas, encouraging similar or slightly warmer high temperatures compared to today, especially for the valleys. Minor HeatRisk will be one of the main threats for the short term, peaking today and tomorrow as valleys and inland spots reach the 80s and interior areas reach the 90s. Despite this warming trend, model guidance has actually been over-performing with highs for the South Bay as it struggles to resolve the shallower marine layer. Have lowered temps slightly for each day through Thursday, primarily for the areas where marine layer influence will linger into the late morning/early afternoon.

The other primary concern remains the long-period southerly swell impacting the Pacific Coast beaches into Wednesday afternoon. There is a high risk for sneaker waves and strong rip currents...never turn your back to the ocean. Additional information can be found in the Beach Hazard Statement and the Beaches discussion section below.

LONG TERM
Issued at 1219 PM PDT Tue Jun 23 2026 (Wednesday night through next Monday)

A large upper-level low will start meandering down along the Canadian coastline for the latter half of the week, decreasing heights over the region with a much deeper marine layer Friday and into the weekend. As cooler, moist air fills in, marine layer depth should push closer to 1500-2000ft as early as Friday morning, with significantly cooler temperatures for interior areas. Highs will fall 4-8 degrees Friday compared to Thursday for inland spots, with further cooling into Saturday as heights continue to fall with the approach of the low. By Saturday morning, the marine layer will be deep enough to support patchy drizzle, primarily for the coastal areas.

As the low approaches, a tightening gradient will bring gusty onshore winds for much of the region as early as Friday, with higher confidence for Saturday and Sunday. Gusts may exceed 40 mph at times, especially for wind-prone areas and mountain passes. Winds weaken Sunday as the low moves up into Montana and weak ridging will attempt to move back into the area. At this time, some long-range models suggest a prevailing troughing pattern that may limit warming for next week, but temperatures should improve a bit compared to the Friday/Saturday cooldown.

AVIATION
(06Z TAFS)
Issued at 903 PM PDT Tue Jun 23 2026

It's VFR except for stratus /MVFR-IFR/ along the immediate coastline. Stratus /MVFR-IFR/ moves inland tonight and Wednesday morning. Stratus mixes out to the coastline with conditions improving to MVFR-VFR by late Wednesday morning and afternoon.
Coastal stratus redevelops Wednesday night and Thursday morning.

Vicinity of SFO...Stratus /MVFR-IFR/ prevails tonight and Wednesday morning with mix out to VFR 19z Wednesday. Stratus /MVFR-IFR/ returns Wednesday evening. West to northwest wind 5 to 12 knots tonight then increasing to near 15 knots beginning 19z Wednesday, then easing to 5 to 10 knots late Wednesday evening.

SFO Bridge Approach...Similar to SFO.

Vicinity of SJC and OAK...For SJC Airport VFR for the evening, then stratus /MVFR/ develops overnight then mixes out to VFR 17z Wednesday. Northwest wind 5 to 10 knots decreasing to light and variable wind early Wednesday morning then northwest near 15 knots Wednesday afternoon. For OAK Airport stratus /MVFR-IFR/ prevails tonight and Wednesday morning, mixing out to VFR 19z. Stratus /MVFR-IFR/ returns Wednesday evening. West wind 5 to 15 knots.

Monterey Bay Terminals...Stratus /MVFR-IFR/ moves inland tonight and Wednesday morning. Conditions improving to MVFR-VFR late Wednesday morning and afternoon. Stratus /MVFR-IFR/ returns Wednesday evening and night. Onshore winds 5 to 15 knots.

MARINE
(Tonight through next Monday)
Issued at 815 PM PDT Tue Jun 23 2026

Gentle to moderate winds will persist through midday Wednesday with generally moderate seas. Fresh to strong breezes and rough seas are forecast to resume over the coastal waters late in the week. Hazardous conditions for small craft will develop Wednesday afternoon and continue through at least Thursday for the northern outer waters. Long period southwest swell will persist through the extended forecast.

BEACHES
Updated at 1215 AM PDT Tue Jun 22 2026

Long period southerly swell at around 14 to 16 seconds will increase to 17 to 19 seconds by the middle of the week as energetic storms in the Southern Hemisphere continue to affect the California coast, especially for south and southwest facing beaches. Hazardous beach conditions are advertised, specifically for moderate to steeply sloped beaches along the Pacific Coast of the North Bay, San Mateo, Santa Cruz counties. A Beach Hazards Statement for Pacific Coast beaches continues through Wednesday afternoon. Be sure to check beach conditions before you head out.
Sneaker waves will run up the beach much farther than other waves, potentially catching beachgoers by surprise and resulting in people being swept into the water. Rip currents are strong enough to pull the strongest swimmers away from shore. Swim near a lifeguard if possible. Stay back from the beach, and away from jetties, piers, beachside rocks, and other infrastructure near the water. Never turn your back to the ocean!

MTR WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement through Wednesday afternoon for CAZ006- 505-509-529-530.

PZ...Small Craft Advisory from 3 PM Wednesday to 3 AM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM.