Parlementia seasonal overview
Best Surf Season (October - March)
The North Atlantic flexes its muscles from October through March, delivering consistent, powerful groundswells that march straight into Parlementia's NW-facing bay. Average surf heights sit in the 1.3-1.8m range with periods of 11-13s, meaning you get pumping, heavy waves during the peak. Offshore winds (S/SSW/SW/WSW) blow 36-51% of the time, often triggered by highs building over the Bay of Biscay. The NAO index tends to be negative or neutral, steering the jet stream south and fuelling extratropical storms that send long-period WNW and NW swell right in. When it all aligns, Parlementia fires.
Fair Surf Season (April & September)
April and September are transitional months where the swell machine slows but still offers fun, rippable waves. Average heights dip to 1.1-1.2m with periods around 10.6-11.0s – still punchy, but less consistent. Offshore wind frequency drops to 29%, making it a game of reading the charts. The Azores High starts to nudge north in April and retreats in September, mixing in longer gaps between groundswells and more variable conditions. You won't score epic sessions every day, but when the combo works, the lineup is uncrowded and the waves are solid.
Low Surf Season (May - August)
Summer in the Bay of Biscay is a quiet affair. From May to August, average swell height hovers around 0.9-1.0m and periods drop to 9.0-10.1s – mostly small, fun-sized grovelers. The dominant NW windswell is often accompanied by onshore winds (W/WNW/NW/NNW) that blow 40-50% of the time, leaving only 15-23% offshore conditions. The Azores High parks itself over the region, producing light but often unfavourable breezes. While micro-sessions on a longboard are possible, don't expect firing waves. The odd late-summer hurricane remnant or distant low can produce a brief spike, but reliability is low.
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Conditions at Parlementia in December
December: Peak Winter, Maximum Potential
December delivers the highest offshore wind frequency of the year at 51%. Average swell height is 1.7m, period 12.6s – very powerful. Swell comes predominantly from WNW (39.6%) and NW (32.4%), with a notable 10.9% coming from straight W – still good, but less direct. The wind rose shows strong S and SSW quadrants (13.7% + 10.5%) that groom the waves to perfection. December is the apex of winter; the energy is relentless. With active lows rolling off the Atlantic, you can count on solid swell almost every day. The only catch is stronger winds sometimes accompany the fronts, but the plus side is longer periods and bigger sizes. If you want to charge, December is your month.
Average Spot conditions at Parlementia in December
Swell history for December
Wind history for December
Swell quality
Analyze the groundswell consistency at Parlementia during December. 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 Parlementia for your next trip in December.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Parlementia for December. 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 Parlementia.
