Surf Forecasts:
Aha Rivermouth surf forecast from 31 Aug 2026:
- Best quality surf: Thursday 3 Sep, 9AM (local time) - 6ft (1.9m), 10s period, E swell with glassy winds.
- Most powerful swell: Tuesday 1 Sep, 6PM (local time) - 8ft (2.5m), 9s period, E swell with 1,224 kJ wave energy.
- Next surfable swell (1★+): Thursday 3 Sep, 9AM (local time) - 6ft (1.9m), 10s period with E 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 Thursday (Sep 03) at 9AM. The primary swell is predicted to be 1.9m and 10s period with a secondary swell of 0.1m and 16s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Aha Rivermouth in the next 16 days are 2.5m 9s and forecast to arrive on Tuesday (Sep 01) at 6PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 10s period and expected on Friday (Sep 04) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9AM (Thu 3rd Sep) | 6ft (1.9m) 10s |
| Best Surf | 9AM (Thu 3rd Sep) | 6ft (1.9m) 10s |
| Most Powerful | 6PM (Tue 1st Sep) | 8ft (2.5m) 9s |
Table - best surf conditions forecast for Aha Rivermouth over the next 16 days.
The Lowdown
Howdy, Rusty here. Let’s be real – the next 16 days at Aha Rivermouth are a grind. There’s a big dry spell at the start with no surf worth mentioning. From Monday August 31st through Wednesday September 2nd, it’s all onshore wind and building swell that’s just a mess. The wind is blowing 18 to 25 mph from the east, cross-on and cross, and it’s lumpy and choppy. The swell energy climbs from 207 (moderate) up to a big 1233 (strong) on Tuesday afternoon, but it’s all blown out.
Then we get a window. Thursday September 3rd is the one to circle. The morning is glassy with a light NNE breeze at 3 mph, and the swell is 6 ft from the east with a 10-second period. The energy is still solid at 745 (moderate), and the water temp is a warm 82°, which is about average for this time of year. This is the only morning that looks really good – clean, lined-up waves, and the Rivermouth should handle that east swell. The afternoon cleans up too with a light cross-offshore, but the swell drops to 5 ft.
After that, it fades quick. Friday the 4th and Saturday the 5th have smaller swell – 3 ft to 3 ft – and while the wind is okay, the energy is weak (122 to 214), and the surf just isn’t there. Sunday the 6th is tiny and onshore. Then from Monday the 7th through to September 15th, it’s a long run of poor surf. The swell kicks up again on the 8th and 9th with 7 ft to 8 ft from the east-northeast, and periods stretch to 12 seconds, so there’s real energy (1222 to 1568, very strong), but the wind is cross-on or onshore at 12 to 22 mph, making it choppy and messy. The 9th has a marginal call, but it’s not worth the bother. The rest of the second week is a mix of onshore wind and fading swell, with nothing to recommend.
So, the only real chance is Thursday morning the 3rd. There’s a long dry spell before and after. Aha Rivermouth can be inconsistent, but this stretch is just tough. The water’s warm, but the wind won’t let us have fun. Keep an eye on the forecasts, but for now, I’d stay home.
Rusty.
Short Range ForecastModerate rain (total 19mm), heaviest on Tue morning. Warm (max 28°C on Mon morning, min 27°C on Mon morning). Winds decreasing (strong winds from the E on Mon night, light winds from the E by Wed night). | Days 4-6 Weather SummaryLight rain (total 4mm), mostly falling on Thu night. Warm (max 29°C on Thu afternoon, min 27°C on Thu morning). Wind will be generally light. | ||||||||||||||||||||
Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | |||||||||||||||
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) | ESE 7 | ESE 9 | ESE 8 | ESE 9 | ESE 9 | E 9 | E 9 | E 9 | E 10 | E 10 | E 10 | E 10 | E 9 | E 9 | E 9 | N 10 | N 10 | N 9 | N 8 | N 8 | E 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 167 | 466 | 599 | 951 | 1215 | 1183 | 985 | 977 | 1019 | 740 | 386 | 220 | 132 | 99 | 80 | 148 | 216 | 160 | 58 | 42 | 78 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross | cross-on | glassy | cross-off | cross-off | cross-off | cross-off | cross | cross | cross | cross-on | cross-on | on | cross-on |
High Tide | 8:34PM2.03m | 9:00AM1.97m | 9:03PM2.00m | 9:45AM1.84m | 9:34PM1.95m | 10:38AM1.67m | 10:11PM1.87m | 11:54AM1.50m | 10:59PM1.76m | 2:11PM1.44m | 00:22AM1.66m | 4:12PM1.54m | 2:30AM1.65m | ||||||||
Low Tide | 2:28PM0.49m | 2:48AM0.43m | 2:59PM0.63m | 3:28AM0.42m | 3:32PM0.79m | 4:15AM0.47m | 4:07PM0.97m | 5:15AM0.55m | 4:54PM1.15m | 6:40AM0.62m | 6:28PM1.30m | 8:28AM0.61m | 9:01PM1.29m | ||||||||
 |  |  |  | |  | | | | | |  | | | | | |  | | | | |
 | 6:05 | — | — | 6:05 | — | — | 6:05 | — | — | 6:05 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — | — |
 | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — |
mm | — | — | — | 3 | 2 | 7 | 3 | 1 | 3 | — | — | 3 | — | — | 1 | — | — | — | — | — | — |
Temp °C | 28 | 28 | 27 | 28 | 28 | 27 | 28 | 28 | 27 | 28 | 29 | 28 | 29 | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 27 |
Feels °C | 28 | 28 | 27 | 27 | 28 | 26 | 27 | 28 | 26 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 31 | 31 | 31 | 31 | 30 |
Swell 1 Height (m) Direction Period (s) | SSW 9 | S 8 | SSW 8 | SW 10 | S 8 | SW 10 | SSW 10 | SSW 10 | E 10 | E 10 | E 10 | E 10 | S 9 | S 9 | S 9 | S 9 | N 10 | N 9 | S 9 | S 8 | SSW 8 |
| kJ | 45 | 52 | 14 | 14 | 12 | 37 | 86 | 127 | 1019 | 740 | 386 | 220 | 168 | 246 | 207 | 158 | 216 | 160 | 119 | 230 | 87 |
Swell 2 Height (m) Direction Period (s) | ENE 11 | SW 9 | SW 9 | S 8 | SW 9 | S 8 | E 12 | — | SSW 10 | E 16 | SW 12 | SSW 10 | E 9 | E 9 | E 9 | N 10 | S 8 | SSW 8 | SSW 8 | N 8 | N 9 |
| kJ | 40 | 13 | 13 | 5 | 14 | 10 | 11 | — | 178 | 5 | 137 | 154 | 132 | 99 | 80 | 148 | 144 | 115 | 92 | 42 | 36 |
Swell 3 Height (m) Direction Period (s) | S 8 | — | S 8 | SSW 8 | E 15 | E 13 | — | — | — | — | NNE 6 | SW 12 | SW 10 | N 7 | N 6 | E 10 | E 10 | E 9 | N 8 | E 9 | N 8 |
| kJ | 12 | — | 5 | 7 | 18 | 14 | — | — | — | — | 13 | 87 | 63 | 23 | 20 | 66 | 68 | 41 | 58 | 39 | 12 |
Wind waves Height (m) Direction Period (s) | ESE 7 | ESE 9 | ESE 8 | ESE 9 | ESE 9 | E 9 | E 9 | E 9 | — | SW 10 | SSW 8 | — | — | — | — | — | — | SE 4 | ESE 4 | E 4 | E 5 |
| kJ | 167 | 466 | 599 | 951 | 1215 | 1183 | 985 | 977 | — | 207 | 125 | — | — | — | — | — | — | 23 | 8 | 8 | 78 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 70 | 69 | 595 | 685 | 673 | 595 | 664 | 664 | 66 | 0 | 0 | 12 | 12 | 70 | 12 | 12 | 40 | 40 | 12 | 60 | 68 |
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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