Porthleven - surf spot statistics

Best Surf Season (October - March)

The heart of the North Atlantic winter drives Porthleven’s most powerful surf. From October through March, the average swell height consistently sits above 1.9m, peaking at 2.5m in January and December, with long-period groundswells (averaging 10-12s) from the deep Atlantic. These swells arrive predominantly from the W, WSW, and SW – right in the window for this south-west facing beach. The catch? The wind is ideal for surfing only 13-19% of the time, as low-pressure systems tracking across the North Atlantic frequently deliver strong onshore winds from the SW-WSW quadrant. However, when dynamic winter high pressure builds or a post-frontal ridge sets up, north to north-easterly offshore winds align to groom the powerful, long-period swell into clean, hollow peaks. This is the time for the firing 1.5-2.5m+ days that make Porthleven a true winter charger.

Fair Surf Season (April - June & September)

As the seasonal transition kicks in, April through June, and later September, offer a trade-off: the swell drops to average heights of 1.2-1.6m with periods shortening to 8-10s, but the frequency of favorable offshore wind conditions improves markedly. During these months, the wind is ideal for surfing 23-26% of the time, thanks to more frequent high-pressure ridges or northerly flows. The swell mix shifts away from pure SW-WSW lines, with more W and WNW energy filling in. While the waves are smaller – often rippable 1-1.5m – the cleaner conditions and lighter winds make for long, fun sessions. September in particular sees a notable bump in average swell height to 1.4m and period to 9.5s, a welcome hint of the coming winter power.

Low Surf Season (July - August)

Summer settles over Porthleven with the smallest and weakest surf of the year. Average swell heights hover around a modest 1.2m, and wave periods drop to 8.2-8.4s – typical of short-period, windswell-dominated conditions. The dominant swell direction remains overwhelmingly from the W and WSW, but the lack of strong storm activity in the Atlantic means these are mostly low-energy, lumpy waves. While the percentage of ideal offshore wind is still decent at 21%, the swell just isn't there to capitalize. On bigger days, expect fun-sized 0.5-1.5m waves that are best suited to groveling or small-wave boards. For consistent quality surf, summer is the slow season – but the occasional longer-period pulse can still deliver a pleasant session.

December: Deep Atlantic Power

December is the climax of the winter season. The average swell height is 2.5m – tying with January for the highest – and the period is a strong 11.2s. The swell direction is dominated by W (16.6%), WSW (12.2%), and SW (6.2%), with a significant portion from S-SSW (5.0% combined) adding variety. This is the month of very powerful, long period swells generated by the deepest lows. The wind ideal percentage sinks to the year's low at 13%, with onshore south-westerlies (SSW 8.5%, SW 10.4%, WSW 11.6%, W 9.7) reigning supreme. The 2-2.5m and over 2.5m wave height ranges are substantial, meaning when conditions do align, you can expect epic, heavy, pumping surf. The short winter days and frequent storms make December a challenging month, but for those who can read the weather and find the offshore windows, Porthleven delivers some of the most memorable sessions of the year.