Aoshima Harbour Surf Forecast and Surf Report

G’day, Rusty here. Let’s break down what Aoshima Harbour is serving up over the next couple of weeks.

The first few days are pretty grim, I won’t lie. Monday morning (14 September) has tiny 4ft swell from the ESE with a short 8-second period, but a cross-onshore breeze makes it messy and marginal. Monday afternoon gets worse with a cross-shore wind and a risk of thunderstorms. Tuesday morning (15 September) offers a brief glimmer: the swell picks up to 5ft from the ESE with a 10-second period, and it’s glassy – dead calm – which would give clean, fun waves. The combined energy is moderate at 401. That’s the best early session, but it’s only rated as "expect good surf conditions," not a standout. Tuesday afternoon stays small with a light cross-shore wind, then from Wednesday (16 September) through Friday (18 September) we’re stuck with weak 3ft to 4ft ESE swell, cross-onshore winds, and combined energy barely cracking 200-300. Choppy and poor – not worth paddling out.

Then things get crazy. Saturday and Sunday (19-20 September) see a big jump in swell – 8ft to 15ft from the ESE, with long 15-16 second periods, and the combined energy rockets into the thousands (4117 to 8206). Sounds good, right? But the wind is howling cross-onshore at 16-22 mph, creating lumpy, blown-out conditions. The swell is too big and the wind is wrong – this setup looks more interesting for kite surfing than paddle surfing. Monday (21 September) is even worse: 16ft swell with near-gale force winds at 34-37 mph. Stay out of the water.

Finally, a real standout emerges on Tuesday morning (22 September). The swell drops to 8ft from the E with a 12-second period, combined energy is still strong at 1857, and the wind shifts to a light 6 mph cross-offshore from the W. It’s clean, powerful, and lined up. That’s expert-level size (over 8ft), so only for experienced surfers, but the conditions are described as excellent. The long period (12s) means better-shaped waves and longer gaps between sets – perfect for the harbour setup, which is a beach/jetty mix and picks up swell from the SE optimum direction. Crowds are only "sometimes" an issue, so you might have it relatively quiet. If you’ve got the skills, this is the session to aim for. Tuesday afternoon drops to 7ft with a light cross-onshore breeze, still decent but not as clean.

After that, it trails off. Wednesday (23 September) to Friday (25 September) is back to weak 2ft to 5ft E swell with moderate cross-onshore winds and combined energy below 850. Poor conditions. Saturday (26 September) stays small and choppy. Sunday (27 September) sees a jump to 7ft from the SE with a 15-second period and combined energy of 1927-2001, but the winds are cross-onshore or unknown, and the forecast is only marginal – not enough to recommend. Monday and Tuesday (28-29 September) bring massive 10ft to 16ft SSE groundswell with very long 16-17 second periods and extreme combined energy (5267 to 12884), but the swell is simply too big for Aoshima Harbour – the forecast notes say so explicitly. Even with favourable wind, it’s dangerous for all but the most experienced big-wave chargers.

Overall, there’s a long dry spell from the start until Tuesday 22 September, which is your one true standout. The rest of the window is either too small and onshore or too big and blown out. Hang in there.

Rusty.

Read more