Belharra - surf spot statistics

Best Surf Season (October - March)

The North Atlantic transforms into a relentless swell machine from October through March, delivering the most consistent and powerful surf to Belharra. During these months, the average swell height hovers around 2.0m, with periods routinely exceeding 12 seconds—a sign of long-period, groundswell energy that this deep-water reef thrives on. The dominant swell directions of NW, WNW, and NNW align almost perfectly with the spot's N/NW exposure, while the prevalence of high-pressure systems over Europe and the Azores generates frequent S, SSW, and SO offshore winds. The combination of large, well-organized swells and clean offshore flow creates the ideal conditions for heavy, tubing waves that Belharra is famous for. The storm track across the North Atlantic is most active now, with powerful extratropical cyclones spinning up fetch that aim straight at the Basque Coast. When the NAO index dips into a negative phase, we see blocking patterns that hold the low-pressure systems at bay, resulting in extended periods of favorable, light offshore winds. This is the window for charging XXL days at the outer reef.

Fair Surf Season (April & September)

April and September represent transitional windows, where the ocean begins to shift from winter's fury to summer's lull—and back again. In April, the average swell height drops to 1.5m and the period settles to 10.8s, still offering punchy head-high waves but with less consistency. The NW and WNW directions remain dominant, but the wind becomes more variable; the percentage of ideal offshore flow declines to around 26%, as the thermal gradients of spring start mixing in onshore sea breezes. September sees a similar pattern, with an average swell height of 1.3m and period of 10.4s, as the first autumn storms begin to respin the Atlantic. You can still get fun, rippable waves in the 1-1.5m range, and with the wind ideal about 27% of the time, the odds of a clean session with glassy conditions are decent. These months are best for dedicated surfers willing to chase windows, but the real power hasn't fully arrived—or has tapered off.

Low Surf Season (May - August)

From May through August, Belharra experiences its most lackluster surf. Average swell heights drop to around 1.0-1.2m, and periods slip into the sub-10 second range—meaning mostly choppy, weak, short-period windswell that lacks the push to properly light up this deep-water reef. The swell direction remains locked in the NW quadrant, but the energy is far less organized, with vast amounts of swell falling into the 0.5-1m range. The real killer, though, is the wind: the percentage of ideal offshore flow plummets to between 14% and 23%. Instead, the prevailing winds swing around to N, NNW, and NW—directions that are directly onshore and ruin wave quality. Summer's thermal low patterns and the Azores High's northern position funnel those dreaded northwesterly breezes right down the coast. While you might find the occasional groveling session on a fun-sized 1m wave, expect mostly blown-out, weak conditions. The spot is best left to tourism and sightseeing during these months.

May: Summer's Slow Crawl Begins

May marks the official entry into the low surf season, and the numbers confirm the downturn. The average swell height falls to just 1.2m, and the period drops to 9.9s—on the border of average, punchy and starting to feel short and weak. The directional distribution still favors NW (50.9%) and WNW (28.0%), but the vast majority of those swells are tiny: 19.1% of NW swell is in the 0.5-1m range, and 18.1% in the 1-1.5m range. Waves over 1.5m become scarce (only 8.6% in the 1.5-2m class from NW). The wind outlook is grim: only 23% of the time does ideal offshore flow occur. The dominant wind directions shift dramatically to N, WNW, and NW—all onshore or cross-onshore. Combined, N, NNE, NNW, NW, and WNW winds account for nearly 50% of all wind observations. These thermal-driven breezes pick up during the day and destroy any chance of clean surf. The mornings can offer glassy conditions, but the window is short. May is best suited for longboarders or those happy with groveling conditions; for anyone after Belharra's famous power, it's time to focus on other hobbies.