Sines - surf spot statistics

Best Surf Season (October - March)

Winter brings the Atlantic to life, with average swell heights consistently over 2m and periods averaging 12-13 seconds, delivering powerful, long-period groundswell. Although the dominant swell direction is from the NW (which doesn't directly hit the south-facing beach), the frequent passage of strong extratropical cyclones dragging fronts across the Iberian Peninsula often produces pulses of S-SSW-SW swell that wrap perfectly into Sines. Combined with a higher incidence of offshore winds from the north quadrant (N, NNE, NE, NNW), the result is a 50-52% chance of ideal conditions. This is the prime window for pumping, firing waves in the 1.5-2.5m range, and occasionally XL days when the Atlantic aligns.

Fair Surf Season (April & September)

During the transition months of April and September, the storm track starts to shift, yet the ocean remains active. Average swell heights drop to 1.8m (April) and 1.4m (September), with periods around 11 seconds – still yielding solid, rippable waves. The Azores High begins to build or retreat, leading to a more mixed wind regime. Offshore winds from the north still dominate about half the time, but onshore southerlies become more frequent. These months are a classic gambler's window: you might score a clean, long-period SW swell with light N winds, or you might face smaller, choppier conditions. Best for the intermediate surfer looking for fun waves without the winter crowds.

Low Surf Season (May - August)

The summer months are defined by a strong Azores High, which suppresses the Atlantic storm machine. Average swell heights bottom out at 1.3m and periods slip to 8-9 seconds – small, fun-sized waves that require a grovel board. The upside is wind quality: with the thermal low over the Iberian Peninsula, north winds blow consistently, making offshore conditions (N, NNE, NW, NNW) the norm. In fact, ideal wind percentages peak at 55-61% in this period, meaning many days deliver clean, micro-to-small surf. While you won't chase XXL swells, this is the season for quiet morning sessions with smooth, rippable lines, especially on a longboard or fish.

December: Peak Winter Force

December rounds out the year with an average swell height of 2.3m and period of 12.7s – very powerful, long period groundswell. The wind ideal percentage drops to 47%, the lowest of the year, due to an increase in stormy onshore winds from the south (S to SW totals 14.6%) and west. However, when the high pressure builds in from the north, offshore winds from N (9.9%), NNE (8.1%), NE (7.5%), and NNW (7.4%) create pristine conditions. Swell from the southern quadrants (S to SW) totals 2.6% – still significant. The NW swell is massive (NW 24.6%, WNW 19.3%). December is a month of extremes: you might face howling southerly winds and huge, unsurfable conditions, or you might score a crisp, glassy day with overhead S/SW swell and a light north breeze. It's a month for the dedicated surfer who is willing to check the forecast daily. The reward is some of the charging, epic waves of the year.