Conditions at Rossnowlagh in May
May: Lighter Swells and Longer Days
May is the edge of the summer lull. Average swell height falls to 0.9m (around 3ft) and average period drops to 9.6s, so the character of the surf shifts from powerful groundswell to more punchy, short-period waves. WNW remains the dominant swell direction at 25.7%, with NW and NNW contributing 19.6% and 19.5%, and W at 16.4%. Most of that energy is small: the 0.5-1m class dominates, with only modest amounts of 1-1.5m swell. Ideal wind is around 26%, and with lighter winds overall plus more frequent NNW/NNE flow, there will be clean, playful mornings on the lower tides. Water temperatures climb to 11.4°C, air temps reach 10.2°C, and rainfall stays moderate at 2.9mm/day. Not the month to chase size, but a good month for logging waves and enjoying longer daylight.
Average Spot conditions at Rossnowlagh in May
Swell history for May
Wind history for May
Swell quality
Analyze the groundswell consistency at Rossnowlagh 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 Rossnowlagh for your next trip in May.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Rossnowlagh 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 Rossnowlagh.