Arenillas - surf spot statistics

Best Surf Season (October - March)

The North Atlantic winter pattern delivers consistent, powerful swell from the NW quadrant. However, at Arenillas, the ideal window aligns when the swell swings more northerly (N to NNE) and is accompanied by offshore S-SSW winds. These months see the highest average wave heights (1.5m-2.0m) and longest periods (11-14s), providing a solid platform for good surf. The percentage of ideal wind conditions peaks at 38-42%, meaning that a significant portion of the days offer clean, offshore conditions. The combination of long-period groundswell and favorable wind makes this the prime time for Arenillas.

Fair Surf Season (April & September)

Shoulder months see a transition. April still has moderate swell (1.4m avg, 10.9s period) but ideal wind drops to 31%. September sees similar stats (1.2m, 10.4s, 32%). The swell direction remains predominantly from the NW, but the wind patterns become more variable, with fewer consistent offshore windows. You can still score good waves, but you'll need to be selective.

Low Surf Season (May - August)

The summer months bring smaller, weaker swell (0.9-1.1m, periods 8-10s). The dominant NW swell is still present but much less organized, often mixed with short-period windswell. Ideal wind percentages drop to 22-30%, meaning onshore winds (from N-NW) frequently ruin the waves. The surf is generally small and mushy, with only rare opportunities for decent waves when a southerly breeze cleans up the leftover swell. This is a time for groveling and longboard sessions at best.

July: The Doldrums of Summer

July is the absolute nadir for surf at Arenillas. Average swell height drops to 0.9m and period to 8.9s – the lowest of the year. The NW directional dominance is extreme (59.8%), with most of that in the 0.5-1m range (33.7%). Ideal wind is at a mere 22%. Onshore winds from the N-NW blow over 20% of the time, further destroying any semblance of a wave. Occasionally, a weak easterly or southerly thermal wind might develop, but the swell is so small that even with clean conditions it’s barely rideable. This month is for dawn patrol with a longboard and low expectations, or better, a trip to a more reliable spot.