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 December typically offers consistent but smaller surf, with an average swell height of 0.7m and a healthy 14.0s period, ensuring clean, well-spaced waves. The majority of swell energy comes from SSW, SW, and WSW directions, with the most common wave heights in the 0.5-1.5m range—ideal for performance surfing. Larger swells (1.5-2.5m) are rare but possible, particularly from SW and WSW, adding variety for advanced riders. Wind conditions are favorable 32% of the time, usually light offshore (E-NE) or calm, but onshore winds (W-WSW) can occasionally disrupt quality. Expect a mix of playful, rippable waves and the occasional punchy peak, though bigger winter swells are less frequent here than at other SoCal breaks. December remains a solid month for smooth, technical surfing, especially on mornings with lighter winds.