Trearddur Bay (Holy Island) Surf Forecast and Surf Report

Alright folks, Rusty here. Let’s have a look at what Trearddur Bay (Holy Island) has in store for us over the next couple of weeks. I’ll be straight with you—it’s a tough stretch ahead, so don’t get your hopes up for any hero sessions.

We’re starting off on Tuesday the 18th of August with next to nothing. The water’s sitting at a touch warmer than average for the time of year at 63°F, but that’s about the only good news. A small 2ft SW swell is getting chopped up by a 12 mph cross-on wind. The combined energy is weak at just 52, and the conditions are poor. We roll through Wednesday and Thursday with the same story—tiny, messy, and not worth paddling out for. By Friday the 21st the swell drops to a meagre 0.3ft, and while the wind turns cross-off and clean, there’s simply no push. That tiny 0.3ft of SW groundswell carries an incredibly long period of 14–15 seconds, but with combined energy as low as 15 or even 7–8, it’s not going to produce a single ridable wave.

This flat spell sticks around through the weekend and into Monday the 24th. Monday morning is glassy with zero wind, but the swell is still a pathetic 0.3ft of long-period SW groundswell—combined energy of just 8. You could water-ski, but not surf. Then Tuesday the 25th brings a bit of a bump, with 3ft of short-period S swell getting blown out by strong 19 mph cross-on winds; it’s lumpy and poor, and combined energy only reaches 25–40.

The pattern continues: small, often onshore, and rarely clean. Thursday the 27th afternoon offers a brief moment when 19 mph ENE offshore winds clean up a tiny 1ft SW swell, but the combined energy is a lowly 24—still borderline unrideable for most. By Friday the 28th, near gale-force winds hit 31–37 mph and the swell is only 0.7ft to 1ft; that’s kite-surfing weather, not surf. The same goes for Saturday the 29th with strong cross-onshore winds making a mess of the tiny swell.

Now, into the first week of September, things finally start to look interesting. On Tuesday the 1st of September, the swell jumps up to 10ft of SW swell with a period of 7 seconds, combined energy a massive 830—that’s strong to very strong wave energy. The wind is cross-off at 25 mph, keeping it clean. However, this is expert-only territory. At over 8ft with short, punchy period, it’s going to be heavy and powerful. The direction is SW, which matches the optimum swell direction for Trearddur Bay. The swell is big and the energy is huge, but with that size and short period, it’s definitely not for the faint of heart. Wednesday the 2nd drops a bit to 6ft, still with moderate combined energy of 214, but the wind swings cross-on and makes it lumpy.

In the end, the only real standout in this entire 16-day window is Tuesday the 1st of September. That’s a solid, powerful, clean swell for the experts. Everything else is a write-off. There’s a long flat spell from the start all the way through to late August, and even the modest bumps are wind-affected. It’s one of those blank runs that’s more normal for this area when the stars don’t align.

Stay patient, and if you’re an experienced surfer, mark the 1st of September on your calendar—but keep an eye on the forecast, as long-range calls are always a bit less certain.

Rusty.

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