Surf Forecasts:
Aha Rivermouth surf forecast from 11 Aug 2026:
- Best quality surf: Wednesday 12 Aug, 3AM (local time) - 3ft (0.9m), 11s period, ENE swell with cross-offshore winds.
- Most powerful swell: Tuesday 11 Aug, 6PM (local time) - 3ft (0.9m), 12s period, ENE swell with 254 kJ wave energy.
- Next surfable swell (1★+): Wednesday 12 Aug, 3AM (local time) - 3ft (0.9m), 11s period with ENE swell.
Best Forecast Surf Conditions for Aha Rivermouth this week:
The surf forecast for Aha Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Aug 12) at 3AM. The primary swell is predicted to be 0.9m and 11s period with a secondary swell of 0.7m and 6s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Aha Rivermouth in the next 16 days are 0.9m 12s and forecast to arrive on Tuesday (Aug 11) at 6PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 10s period and expected on Tuesday (Aug 11) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Wed 12th Aug) | 3ft (0.9m) 11s |
| Best Surf | 3AM (Wed 12th Aug) | 3ft (0.9m) 11s |
| Most Powerful | 6PM (Tue 11th Aug) | 3ft (0.9m) 12s |
Table - best surf conditions forecast for Aha Rivermouth over the next 16 days.
The Lowdown
G’day, Rusty here.
Let’s be straight with you. Aha Rivermouth is a beach and jetty set-up, so it needs the right conditions to really fire, and over this 16-day window, it’s a pretty lean run. The water temp is sitting at 84°, which is about average for this time of year – no surprises there.
The best of a quiet bunch comes on Wednesday 12 August. It’s not big, but we’ve got a small 3ft ENE groundswell rolling in with an 11-second period. That’s a nice long period, meaning better shaped waves with some punch. The real winner is the wind – a light cross-off in the morning, going glassy by Thursday 13th morning with zero wind. That’s proper clean, buttery conditions at a spot that’s fairly consistent. The combined energy is weak to moderate at best (155), so it’s not going to be pumping, but for a sneaky, uncrowded session it’s as good as it gets. The afternoon of Wednesday 12th is also clean with a light westerly. The swell direction (ENE) isn’t the optimum (NE), so it’ll be a bit wonky, but with that wind, it’s worth a look.
After that, things drop off. From Thursday afternoon onwards it’s mostly poor with choppy onshore winds and tiny swell. There’s a big spike on 20 August – an 12ft SE swell hits, but it’s cross-shore and lumpy with fresh breeze. The afternoon actually shows “wind and tide favorable, but the swell is predicted to be too big for this break” – over 10ft and way too much for a jetty spot. The energy is through the roof (1997 / 1730), but it’s a mess, and at that size, it’s for experts only and honestly, it’s likely more interesting for kite surfing.
From 21 August onward, it’s onshore winds and lumpy conditions with swell dropping back to 5-6ft but never clean. The end of the window (26 August) shows a massive 15ft groundswell with a 15-second period and gale force winds – clean offshore, but that’s a beast for big wave chargers only, and far out in the second week so less certain. Not a paddle-friendly setup for most.
In short: Wednesday 12th morning is the standout. Tiny, clean, and uncrowded. The rest is a write-off or too big and messy.
Rusty.
Short Range ForecastHeavy rain (total 32mm), heaviest during Tue morning. Warm (max 28°C on Tue morning, min 26°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 11mm), heaviest on Fri morning. Warm (max 29°C on Sun afternoon, min 27°C on Fri morning). Mainly fresh winds. | ||||||||||||||||||||
Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map |  |  |  |  |  |  |  | ||||||||||||||
Wave Height (m) Direction Period (s) | ENE 12 | ENE 12 | ENE 12 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | S 8 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 240 | 254 | 193 | 135 | 130 | 77 | 114 | 92 | 57 | 33 | 31 | 0 | 93 | 101 | 136 | 136 | 116 | 77 | 75 | 80 | 125 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross | cross-off | cross-off | glassy | glassy | cross-off | cross-off | cross-off | cross-off | cross | cross | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on |
High Tide | 6:35PM1.89m | 5:53AM2.06m | 7:07PM1.97m | 6:38AM2.14m | 7:37PM2.02m | 7:20AM2.16m | 8:06PM2.05m | 8:00AM2.13m | 8:34PM2.06m | 8:38AM2.05m | 9:03PM2.03m | 9:16AM1.92m | 9:31PM1.98m | ||||||||
Low Tide | 11:55AM0.21m | 00:07AM0.93m | 12:36PM0.15m | 00:47AM0.79m | 1:14PM0.15m | 1:25AM0.67m | 1:49PM0.20m | 2:01AM0.58m | 2:21PM0.30m | 2:37AM0.53m | 2:51PM0.43m | 3:14AM0.53m | 3:20PM0.59m | ||||||||
 | |  |  | |  |  | | | | | | |  |  | | |  | | | | |
 | 5:56 | — | — | 5:56 | — | — | 5:56 | — | — | 5:56 | — | — | 5:58 | — | — | 5:58 | — | — | 5:58 | — | — |
 | — | 7:07 | — | — | 7:06 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — |
mm | 8 | 3 | 3 | 6 | 4 | — | — | 4 | 4 | 5 | 3 | — | — | — | — | — | — | 3 | — | — | — |
Temp °C | 28 | 28 | 28 | 27 | 28 | 28 | 28 | 28 | 27 | 27 | 27 | 27 | 28 | 28 | 28 | 28 | 29 | 28 | 28 | 28 | 28 |
Feels °C | 30 | 31 | 31 | 31 | 33 | 33 | 33 | 31 | 30 | 29 | 29 | 30 | 30 | 29 | 31 | 31 | 32 | 31 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | S 10 | S 9 | S 9 | S 9 | S 9 | S 8 | SSW 8 | S 8 | W 6 | SSW 8 | S 8 | S 8 | SSW 8 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 |
| kJ | 200 | 211 | 251 | 164 | 126 | 115 | 120 | 66 | 32 | 94 | 50 | 68 | 64 | 101 | 136 | 136 | 116 | 77 | 75 | 75 | 125 |
Swell 2 Height (m) Direction Period (s) | ENE 12 | E 6 | ENE 12 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | S 8 | ENE 10 | SW 8 | SW 9 | ENE 11 | S 8 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 |
| kJ | 240 | 73 | 193 | 135 | 130 | 77 | 114 | 92 | 49 | 33 | 34 | 28 | 93 | 65 | 64 | 61 | 64 | 67 | 40 | 39 | 41 |
Swell 3 Height (m) Direction Period (s) | SSW 10 | ENE 12 | WSW 10 | ESE 6 | SW 9 | N 9 | N 8 | SW 8 | ENE 10 | N 6 | ENE 10 | W 6 | S 8 | SSW 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 8 | S 8 |
| kJ | 157 | 254 | 36 | 20 | 27 | 37 | 28 | 35 | 57 | 7 | 31 | 12 | 34 | 52 | 49 | 48 | 49 | 32 | 31 | 29 | 18 |
Wind waves Height (m) Direction Period (s) | E 6 | — | ESE 6 | — | — | ESE 6 | ENE 2 | — | W 6 | W 6 | WNW 8 | — | SSE 3 | — | — | — | E 6 | E 5 | E 5 | E 5 | ESE 6 |
| kJ | 61 | — | 48 | — | — | 10 | 1 | — | 17 | 22 | 33 | — | 1 | — | — | — | 15 | 14 | 27 | 80 | 97 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 60 | 12 | 12 | 0 | 0 | 0 | 0 | 78 | 75 | 90 | 75 | 68 | 30 | 75 | 68 | 44 | 68 | 68 | 68 | 68 | 70 |
Best forecast wave conditions in Okinawa | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
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Information about the Aha Rivermouth Surf forecast
The above surf forecast table for Aha Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Aha Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Aha Rivermouth surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Aha Rivermouth) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).
Further information to help with frequently asked questions about our surf forecast for Aha Rivermouth may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.
Aha Rivermouth is 31 km (19 miles) from the city of Okinawa. If you plan a holiday in Okinawa, look for hotels and other accommodation in Okinawa. Okinawa has rooms for a wide range of budgets as well as car hire and transport links.
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