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.

December: Midwinter Peak, Finest Conditions

December is statistically the best month of the year for Guethary. The average swell height reaches 1.7m with a period of 12.6s, and an impressive 25.4% of the total swell is in the 1.5-2.5m range from WNW and NW alone. The swell direction remains dominated by WNW (39.6%) and NW (32.4%), with a notable increase in W swell (3.8%) that can deliver extra juice when aligned with the wind. The big news is the wind: ideal offshore conditions occur a full 50% of the time – the highest of any month. The primary offshore directions are S (13.7%) and SSW (10.5%), often linked to a strong high-pressure ridge over the continent that funnels clean, dry air out to sea. Onshore westerlies (W, WNW, NW) still occur but are less frequent than in autumn. December’s combination of powerful, long-period swell and excellent offshore wind odds creates the perfect recipe for classic Guethary: steep, hollow lefts and rights with plenty of wall. The water may be chilly, but the quality is unmatched. This is the month to clear your schedule and commit to the Basque winter.