Sesimbra - surf spot statistics

Best Surf Season (October - March)

The North Atlantic awakens in autumn, and Sesimbra feels the pulse as powerful low-pressure systems track across the ocean. While the dominant swell direction remains from the NW quadrant, the frequency and intensity of S to SW swell increase markedly during this window. These are the months when the beach's SSW exposure can truly light up, especially when a deep depression stalls west of Portugal, firing long-period groundswell from the S or SW. Combined with the reliable offshore winds from the N to NNE quadrants (which blow 45-48% of the time), the setup for quality surf is unmatched. Expect average wave heights of 1.5-2.0m with periods often exceeding 12s, delivering powerful, rippable waves. A negative NAO index often amplifies the storm track, funnelling more favourable swell angles towards Sesimbra.

Fair Surf Season (April & September)

These transition months offer a blend of the fading winter energy and building summer stability. The average swell height drops to 1.1-1.5m, and periods shorten slightly (10-11s). The swell direction still swings from the SW to NW, but the mix becomes less consistent. April can deliver lingering winter swells with clean N winds, while September sees the first hints of autumn storms. The offshore wind frequency hovers at 43-50%, meaning favourable days are interspersed with lighter onshore flows. It is a solid shoulder season for the dedicated surfer who is willing to chase the windows.

Low Surf Season (May - August)

Summer settles in, and the Atlantic storm track retreats north. The dominant swell is overwhelmingly from the NW and NNW (accounting for over 70% of the total swell energy in June and July). This direction, while producing rideable waves, does not align well with the SSW-facing beach; the resulting waves are often smaller, weak, and prone to refraction that reduces their quality. Average wave heights hover around 1.0m with periods under 10s, leading to choppy, grovelly conditions for the most part. The wind is ideal only about 42-46% of the time, with strong NNW thermal winds frequently creating a side-shore breeze that further complicates the surf. Occasional pulses of S-SW swell can still break the monotony, but these are rare and quickly dashed by summer high pressure.

September: Autumn Stirrings

September is the turning point. Average wave height increases to 1.1m and period to 10.5s. The swell energy starts to shift: the NW quadrant (NW and WNW) dominates at 82.0%, but the S-SW direction (SW, SSW, S) appears at 1.3% – a doubling from summer. The offshore wind frequency jumps to 50%, the highest of the year, and N winds account for 15.8%, while NNW winds are at 20.5%. This combo means more glassy mornings and afternoons with a steady, if small, swell. The first true late-season lows begin to form, and when they track far enough south, they deliver S-SW groundswell with long periods. By the end of the month, the surf season is definitely back on.