Conditions at Rossnowlagh in December
December: Deep Winter Classic
December wraps up the year with Rossnowlagh in peak form. Average swell height is 1.7m (around 5-6ft) and average period inches up to 12.2s, giving the surf long-period muscle. The western swell window remains wide open: WNW at 27.1%, W at 20.4%, NW at 12.5%, and NNW at 8.8%, with WSW adding another 7.3%. The height distribution is what stands out in winter -- W and WNW both have strong percentages of 1.5-2m and 2-2.5m waves, plus 0.6% from WNW above 2.5m. That means serious, firing days when the conditions align. Wind statistics tell a familiar story: SSW and SW each around 10.4%, S 9.9%, and WSW 9.5% put plenty of onshore chop in the mix, but 26% ideal wind keeps the door open for clean winter bombs. Water temp is 9.9°C, air averages 5.0°C, and daily rain near 4.6mm means the whole place is soaking and alive.
Average Spot conditions at Rossnowlagh in December
Swell history for December
Wind history for December
Swell quality
Analyze the groundswell consistency at Rossnowlagh during December. 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 December.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Rossnowlagh for December. 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.