Conditions at Ondarreta in May
May: Small but Fun Atlantic Swell
May is the start of the summer pattern. Average swell size drops to 1.2m (4ft) and the period shortens to 9.9s, so the ocean is moving toward average, punchy swell rather than powerful winter groundswell. The swell roses show a huge concentration from the NW (50.9%), with WNW at 28.0% and NNW at 13.2%. Much of that is in the 0.5-1m (2-3ft) and 1-1.5m (3-5ft) range-fun, rippable waves for a shortboard or a groveler.
Winds are the limiting factor. The ideal offshore percentage falls to 36%, and the typical spring breeze comes from NNW (13.5%), WNW (13.1%) and NW (12.4%), which starts to crumble the faces. Still, light S winds around 6.7% and warmer air (15.1°C) can make for mellow mornings. Water temp climbs to 16.1°C; a 3/2 wetsuit is comfortable. May is not the time to expect pumping surf, but it can deliver clean, small waves for the patient surfer.
Average Spot conditions at Ondarreta in May
Swell history for May
Wind history for May
Swell quality
Analyze the groundswell consistency at Ondarreta during May. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Ondarreta for your next trip in May.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Ondarreta for May. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Ondarreta.