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 November typically sees moderate swell conditions with an average height of 0.7m and a solid period of 14.5s, indicating well-spaced, clean waves. The dominant swell directions are SSW (47.28% combined across all heights) and SW (31.11%), delivering consistent energy to the break. Wave heights mostly fall in the 0.5-1m range (34.94% SSW, 20.78% SW), with occasional larger sets up to 2.5m from WSW and W directions, though these are rare (totaling <1% combined). Wind conditions are favorable 34% of the time, with the most common clean winds being light offshore (N-NE) or light cross-shore (E-ESE). However, onshore winds from WSW-WNW prevail at moderate speeds (10-20kph) around 13.19% of the time, potentially creating choppy conditions. Overall, November offers reliable, waist-to-shoulder-high waves with good shape, particularly on SSW swells, but wind variance means surfers should prioritize early sessions or days with NE influence for glassier conditions.