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Conditions at Upper Trestles in May
May: Southern Hemisphere Swells in a Sea Breeze Fight
The Southern Hemisphere spring and summer swell machine starts delivering more consistently in May, pushing the average period to 13.5s. Wave heights average 3.5ft (1.1m), with an excellent directional mix: WSW 39.5%, SW 30.3%, SSW 7.8% and W 22.1%. The majority of swell now arrives from the S-to-WSW window, exactly what Upper Trestles wants. However, May has the worst wind statistics of the year alongside June, with ideal offshore wind only 9% of the time. S/SSW/SW/WSW winds combine for more than 60% of all wind observations, and the persistent thermal low creates that classic afternoon westerly sickness. Air temps rise to 17.1°C, water to 14.8°C, and precipitation nearly disappears at 0.27 mm/day. There are still excellent early-morning sessions, and if an eddy current brings N/NNE flow, the 3-4ft (1-1.2m) southwest groundswell can turn Lowers into a rippable dream. But quality sessions are fleeting.
Average Spot conditions at Upper Trestles in May
Swell history for May
Wind history for May
Swell quality
Analyze the groundswell consistency at Upper Trestles during May. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Upper Trestles for your next trip in May.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Upper Trestles for May. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Upper Trestles.