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.

July at Upper Trestles is characterized by small but clean conditions, ideal for high-performance surfing. The average swell height is 0.8m with a long 14.8s period, producing consistent, well-spaced waves. The dominant swell direction is SSW, accounting for 63.64% of waves in the 0.5-1m range, ensuring favorable shape and rideability. While larger swells (over 1.5m) are rare, the spot thrives on knee-to-chest-high waves with excellent energy due to the extended period. Wind conditions are crucial—only 28% of the time are they ideal (typically light offshore or glassy), but WSW and W winds (15-20kph) can create chop. Mornings often offer the cleanest sessions before afternoon breezes pick up. Expect a mix of playful, rippable waves with occasional punchier sets when the SSW swell peaks. Advanced surfers will appreciate the technical, fast walls, while the consistency keeps it surfable most days. Bring a high-performance shortboard and patience for the best windows.