Kilcummin - surf spot statistics

Best Surf Season (October - March)

The North Atlantic switches into full-on winter mode from October onward, and Kilcummin feels the brunt of it. Extratropical cyclones marching east across the Atlantic drag cold fronts and pumping W to WNW groundswells across the region. While the beach faces north, the dominant westerly swell spectrum (W, WNW, and NW bands) can wrap nicely into the bay, delivering powerful long-period swell (average period 11-13s) with wave heights in the 1.5-2.5m range. The kicker: southerly quadrant winds (S, SSW, SW) blow directly offshore at Kilcummin, and they occur 34-38% of the time. This is when the stars align – a solid NW swell with a light offshore breeze creates glassy, well-shaped waves. The NAO index often turns negative in winter, backing winds into the south and enhancing the offshore window. January and February are prime, but expect plenty of stormy, onshore days as well.

Fair Surf Season (April & September)

Shoulder months bring a transition. April sees the jet stream weaken, average swell heights drop to 1.2m and periods settle around 10.9s. The swell direction is still dominated by W and WNW, but fewer storms mean less consistency. Wind becomes a bigger factor – ideal offshore winds (S-SSW) still occur ~33% of the time, but lighter speeds (10-20kph) become more common, allowing for fun, rippable conditions when a mid-period NW swell sneaks in. September feels the first bite of autumn: the average swell climbs back to 1.2m and period to 10.3s, with increasing WNW swells. The offshore wind percentage ticks up to 37%, making for some excellent early-season sessions. Both months offer more manageable wave heights for intermediate surfers, though the windows of quality can be short.

Low Surf Season (May - August)

Summer is the quietest period at Kilcummin. The average swell height bottoms out at 0.9-1.0m and periods plummet to 8.8-9.2s, reflecting a mostly windswell regime. Swell direction leans heavily into the W and WNW (over 70% combined), meaning the north-facing beach rarely sees the ideal N or NW swell. The wind patterns are more variable: though S-SSW winds still blow offshore 29-36% of the time, the lighter speeds (0-10kph) and frequent northerly sea breezes (N, NW, NNW winds that are onshore) make it tough to score clean waves. When a north swell does manage to push in – usually from a passing low – it’s often accompanied by onshore northerly winds. The result: mostly small, weak, choppy conditions save for the occasional fun-size summer swell with perfect offshore flow. If you’re willing to grovel on a longboard, there are diamonds in the rough.

May: Small and Fickle

May is a low point in the annual swell cycle. The average swell height is just 1.0m, with period averaging 9.9s – a mix of short-period swell and the occasional longer-period pulse. Swell direction leans heavily into the W (22.0%) and WNW (24.8%), while the NW quadrant (18.0%) and NNW (9.9%) still offer some north components. The good news: the north quadrant (N, NNE, NW, NNW) totals about 29.6% of swell, but the wave heights are often in the 0.5-1m range (grovel territory). Wind conditions are less ideal: offshore flow only 31% of the time, and the northerly quadrant (N, NNE, NE) picks up, creating onshore conditions more often. This month is best suited for a longboard and low expectations. Keep an eye on late-month lows that can spin up a sudden NW swell with a lucky southerly wind window.