Lower Trestles seasonal overview
Best Surf Season (November - February)
Lower Trestles hits its stride from late fall through mid-winter as the North Pacific rumble to life. The combination of powerful, long-period groundswells from the WSW and SW quadrants meets the highest frequency of offshore winds (N, NNE, NE) — peaking at 59% ideal conditions in December. These months deliver consistent 1-1.5m fun-to-solid waves with periods often exceeding 12 seconds, making for rippable A-frames and long walls. The occasional bigger episode from a bomb cyclone can push the reef into pumping 1.5-2.5m territory, though W-dominant swells still require some luck to align with the preferred southerly band.
Fair Surf Season (October & March)
Shoulder months offer a mixed bag. October sees a ramp-up in S/SSW swell energy (9% combined from S/SSW) and improving wind chances (36% ideal), while March retains a good supply of WSW and W swell (83% combined) but offshore wind reliability drops to 31%. These months can produce excellent days when a late-season cold front passes through, cleaning up the water and steering in long-period swell. Expect more variability — some days of clean, shoulder-high surf, others murky and onshore.
Low Surf Season (April - September)
From spring through early fall, Lower Trestles goes quiet. The North Pacific storm track shuts down and the predominant SW and WSW swell is often accompanied by persistent onshore flow from the S, SSW, SW, and WSW — the worst wind directions for this south-facing reef. Ideal wind percentages bottom out between 9% (June) and 14% (August). Swell heights average only 0.9-1.1m, mostly groveling 0.5-1m range, though the period remains surprisingly long (13-14s) thanks to distant Southern Hemisphere storms. The rare combination of a strong southern hemi groundswell with a coastal eddy or Santa Ana wind event can produce brief, fantastic sessions, but those are the exception, not the rule.
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Conditions at Lower Trestles in December
December: Prime Time at Lowers
December is the statistical peak with 59% ideal wind — the highest of the year. Average swell 1.0m and period 12.6s. Swell direction is mostly W (54.6%) and WSW (28.9%), with SW at 10.6%. While W is not the preferred direction, the long period and frequent NE (24.7%) + NNE (10.5%) winds produce clean, well-shaped waves. Many days offer 1-1.5m (18.5% from W alone) with occasional 1.5-2m sets (4.5% from W). When a strong cold front aligns the swell from the SW or WSW with a NE offshore, Lowers can be world-class. This is the month to plan your trip if you want the best combination of power, period, and perfect wind.
Average Spot conditions at Lower Trestles in December
Swell history for December
Wind history for December
Swell quality
Analyze the groundswell consistency at Lower Trestles during December. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Lower Trestles for your next trip in December.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Lower Trestles for December. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Lower Trestles.
