Guethary - surf spot statistics

Best Surf Season (October - March)

The North Atlantic swings into full production mode during these six months, delivering a steady diet of powerful, long-period swell to the NW-facing shores of Guethary. Average wave heights hover between 1.3m and 1.8m, with periods consistently above 11s and often reaching 13s, putting the spot firmly into the pumping and firing categories. The climatalogical dip in the Azores High allows low-pressure systems to barrel across the basin, sending trains of W, WNW, NW and NNW swell straight into the Bay of Biscay. Offshore wind windows – driven by continental high pressure or the eastern flank of passing lows – occur 41-50% of the time, perfect for grooming those long, clean lines. December stands out as the statistical peak, but every month from October through March offers ample opportunity for classic Guethary barrels.

Fair Surf Season (April & September)

April and September represent the shoulder months, where the ocean still holds respectable swell but the consistency and power begin to wane. Average swell heights drop to 1.1-1.2m, periods shorten to 10.6-11.0s, and ideal wind frequency falls to around 29%. Swell directions remain dominated by WNW and NW – the bread and butter for this spot – but the mix is peppered with more small, weak pulses. Spring and autumn transition patterns often bring fickle conditions: some days deliver punchy, rideable waves, others are plagued by onshore breezes from the W or NW. For the patient surfer, these months can still yield solid sessions, especially when a late-season storm sneaks through and a high-pressure ridge parks itself over the continent, producing offshore flow.

Low Surf Season (May - August)

Summer at Guethary is a classic tale of diminished energy. From May through August, average swell heights bottom out at 0.9-1.0m and periods slump to 9.0-10.1s, often producing small, fun-sized or groveling conditions. The dominant swell still arrives from the NW and WNW, but the fetch is generally weak – either from distant tropical systems or lightweight Atlantic lows. More critically, the percentage of ideal offshore wind plummets to 15-23%, as the prevailing regime shifts to spring/summer westerlies and sea breezes that ruin the wave face. While the occasional long-period groundswell can sneak in from a rogue storm, the day-to-day reality is small, wind-affected surf. This is the season to save your energy, explore other spots, or wait for the autumn equinox to reignite the North Atlantic machine.

January: Deep Winter, Big Lines

January is the heart of the Basque winter and Guethary reaps the rewards of a fully active North Atlantic. Average swell height sits at a solid 1.8m with a period of 13.0s, meaning you can expect powerful, long-period surf for most of the month. The swell direction is heavily weighted toward the ideal quadrants: WNW (42.7%) and NW (29.3%) dominate, with a notable 9.0% of waves exceeding 2m and a further 0.9% over 2.5m from WNW alone. That puts many days in the pumping to firing range. Wind statistics show ideal offshore conditions (W, WSW, SW, SSW) 47% of the time – the second-highest of the year. The most common offshore direction is actually S/SSW (a combined ~22%), which blows clean side-offshore across the NW-facing beach. However, strong zonal westerlies (W at 10.3%) can also be a mixed blessing: they bring excellent swell but also onshore flow when the wind shifts slightly north. The key is to watch for high pressure building over the Bay of Biscay or a cold front passage that leaves offshore winds in its wake. When the stars align, January delivers classic Guethary: hollow, racy peaks with plenty of punch.