Altura - surf spot statistics

Altura, Portugal, offers the most consistent surf conditions during the winter months, particularly from November to February. During this period, the swell activity is at its peak, with ground swell percentages improving significantly—up to 21% in January and 20% in December—while wind swell contributes an additional 35-42%. The average swell size hovers around 0.7m, occasionally reaching up to 0.8m in December, providing the most rideable waves of the year. However, wind conditions remain challenging, with bad onshore winds (87-89%) dominating, making clean sessions a rarity. Spring (March-April) sees a decline in ground swell but still maintains decent wind swell activity (41-48%), though wind conditions remain unfavorable. Summer (May-September) is the least consistent, with minimal ground swell (0-4%), weak wind swell (25-45%), and very high percentages of flat days (61-74%). The swell size drops to 0.4-0.6m, and wind conditions worsen further (90-94% bad winds). Autumn (October-November) marks a gradual return of swell energy, with ground swell increasing to 6-9% and wind swell around 37-43%, but wind quality remains poor. For experienced surfers, the best windows are likely in late autumn and early winter when swell consistency improves despite the persistent onshore winds. If you prioritize quality over frequency, December stands out with the largest average swell size and slightly better wind odds (13% clean conditions). Summer is only suitable for beginners due to small, weak waves, while winter offers the most powerful—albeit inconsistent—surf.

December in Altura offers relatively small but rideable conditions, with an average swell height of 0.8m and a decent period of 9.0s, suggesting some consistency in wave quality. The most dominant swell directions are W and WSW, with W swells contributing the largest share of rideable waves (14.36% in the 0.5-1m range and 19.22% in the 0-0.5m range). WSW swells also bring slightly larger waves, with 4.58% in the 0.5-1m category and 6.19% in the smallest range. SE swells occasionally deliver bigger sets (5.48% in 0.5-1m and 1.83% in 1-1.5m), but overall, wave height distribution leans toward smaller, manageable surf. Wind conditions are mixed—ideal only 13% of the time. The predominant winds come from the N/NE/ENE sectors at moderate speeds (10-30kph), which can create onshore chop, but lighter winds (0-10kph) occasionally provide cleaner surfaces, especially during WSW or W wind scenarios. Expect smaller, fun-sized waves with occasional mid-period pulses, but be prepared for variable winds and limited consistency in quality. It's a month for logging time on smaller boards or longboards rather than expecting powerful surf.