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 May typically offers surfable conditions with an average swell height of 0.9m and a solid period of 15.1s, indicating clean, well-spaced waves. The swell distribution shows a dominant SSW direction, with 54.4% of waves in the 0.5-1m range and 12.9% in the 1-1.5m range, while WSW swells bring slightly larger waves (3.36% in 1.5-2m). Wind conditions are favorable 25% of the time, with lighter winds (0-10kph) being most common from SSW (4.15%) and SW (4.9%). However, stronger WSW winds (8.09% in 10-20kph, 2.99% in 20-30kph) can create chop. Overall, May delivers consistent, mid-sized waves with good shape, though wind quality varies—early mornings or protected sessions may yield the best rides. Keep an eye on wind shifts, as SW-WSW breezes can occasionally disrupt conditions.