Upper Trestles - surf spot statistics

Upper Trestles is a high-quality surf spot that benefits from consistent ground swell year-round, though the best conditions are typically found between April and October. During these months, ground swell dominates (90%+ of the time), with minimal wind swell interference, making for clean, well-organized waves. The mean swell size hovers around 0.8-0.9m, providing ideal conditions for performance surfing. However, wind conditions are often less favorable, with bad onshore winds occurring 60-75% of the time, peaking in May and June. The late summer and early fall months (September-October) offer slightly better wind conditions, with good winds around 38-39% of the time, improving wave quality despite the swell size tapering slightly. Winter months (November-March) see more variability, with increased wind swell and no-swell days, while ground swell remains strong but less reliable. December and January have the highest chance of no swell (25-31%) and the smallest average wave heights (0.7m). For the best balance of swell consistency and manageable wind conditions, September and October stand out, though dedicated surfers can find good waves from late spring through early fall if willing to work around the frequent onshore winds.

Upper Trestles in October typically offers consistent but smaller surf, with an average swell height of 0.7m and a solid 15-second period, indicating clean, well-spaced waves. The majority of swell comes from the SSW and SW directions, with moderate wave heights (55.48% between 0.5-1m from SSW, 22.63% from SW). While larger waves over 1.5m are rare, the long period ensures quality rides. Wind conditions are favorable 39% of the time, with light to moderate winds predominantly from the W, WSW, and NW directions, providing offshore or sideshore flow for clean faces. However, stronger onshore winds occasionally occur, mainly from the W and WSW, which can deteriorate conditions. Overall, October delivers reliable, high-performance waves with good shape, best suited for experienced surfers looking for technical, fast-breaking peaks rather than raw power.