Foz do Arelho seasonal overview
Best Surf Season (October - March)
The heart of the surf year at Foz do Arelho runs from October through March. As the North Atlantic storm track ramps up, average swell heights push quickly into the 7-9ft (2.1-2.8m) range and periods lengthen into the powerful 12-13 second band. A negative NAO pattern is often the key: with the jet stream displaced south, Atlantic lows park closer to the Iberian coast and feed long-period NW, WNW and NNW groundswell straight into this northwest-facing beach. December, January and February also post the highest percentages of ideal offshore wind windows, peaking at 32 percent in December. This is when Foz do Arelho delivers consistent head-high to well-overhead sandbar waves.
Fair Surf Season (April, May and September)
April and May are transition months. The ocean is still alive, with average wave heights between 6-7ft (1.8-2.1m) and periods from 9.9 to 11.2s, but the spring wind pattern becomes the main obstacle. Strong N to NNW flow takes over, dropping ideal offshore wind percentages to 13-16 percent and making clean sessions increasingly rare. September marks the first turn of the wheel: the first Atlantic lows spin up, average periods climb back to 10.5s, and water temperatures peak at 18.2C, creating a small but real window for early-autumn quality when the wind flips light offshore.
Low Surf Season (June - August)
Summer is the quietest stretch at Foz do Arelho. Average swell heights bottom out at 5ft (1.5m) in July and August, periods drop to 8.6-9.0s, and the Azores High locks in relentless N to NNW winds. Ideal offshore wind sits at just 4-8 percent, leaving most days lumpy, windblown and small. The swell that does arrive is short-period NW and NNW windswell rather than true groundswell. Occasionally a light E to S breeze aligns with a summer pulse and the beach turns playful, but consistency is poor. For serious surfers, summer is best spent waiting for the autumn transition.