
Surf Forecasts:
Aha Rivermouth surf forecast from 31 Jul 2026:
- Best quality surf: Wednesday 5 Aug, 6PM (local time) - 15ft (4.5m), 19s period, ENE swell with cross-onshore winds.
- Most powerful swell: Thursday 6 Aug, 9PM (local time) - 48ft (14.5m), 17s period, NE swell with 118,626 kJ wave energy.
- Next surfable swell (1★+): Wednesday 5 Aug, 6PM (local time) - 15ft (4.5m), 19s 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 05) at 6PM. The primary swell is predicted to be 4.5m and 19s period with a secondary swell of 2.0m and 7s. The wind is predicted to be cross-onshore as the swell arrives.
The most powerful waves expected at Aha Rivermouth in the next 16 days are 14.5m 17s and forecast to arrive on Thursday (Aug 06) at 9PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 13.0m 13s period and expected on Friday (Aug 07) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Wed 5th Aug) | 15ft (4.5m) 19s |
| Best Surf | 6PM (Wed 5th Aug) | 15ft (4.5m) 19s |
| Most Powerful | 9PM (Thu 6th Aug) | 48ft (14.5m) 17s |
Table - best surf conditions forecast for Aha Rivermouth over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s happening at Aha Rivermouth over the next couple of weeks.
Right off the bat, we’re in a bit of a flat spell. The first real surfable energy doesn’t show up until Sunday morning, August 2nd, and even then it’s a slow start. From now until then, we’re looking at tiny, weak waves with poor conditions, so don’t rush to wax up.
Sunday morning, August 2nd, brings the first glimmer of hope. We’ve got a small 1 ft swell from the east, but here’s the kicker – the period is a very long 16 seconds. That’s proper groundswell energy, and it’s showing up with clean conditions thanks to a light offshore wind. The combined energy is still weak (97), but for a point break or river mouth like this, that long period could produce some surprisingly fun, lined-up waves. It’s a sneaky good window for the patient surfer.
Sunday afternoon gets a bit messy with a cross-onshore wind, but the swell bumps up to 2 ft with a 17-second period and energy climbing to 226. It’s still small, but that long period will keep things interesting.
Monday the 3rd sees the swell jump to 4 ft to 4 ft from the east, with periods still hanging around 15–16 seconds. The energy is now moderate (689 to 861), but the wind goes cross-onshore and choppy, so it’s not the cleanest. Still, there’s power in the water.
Now, the standout period. Tuesday, August 4th, is the day to circle. Morning brings a solid 6 ft east swell with an 18-second period. The wind is light and onshore, but the energy is already strong at 2002. By Tuesday afternoon, the swell hits 7 ft, same long period, and the energy jumps to 3013. This is a serious groundswell. For a rivermouth setup, that long period should wrap in nicely, but it’s getting big – over 8 ft is expert territory. The wind is more onshore, so it won’t be perfect, but the raw power is there.
Wednesday, August 5th, is giant. 10 ft to 13 ft east swell with 18–19 second periods. Energy is off the charts (6104 to 11262). This is heavy, powerful surf. Only for the most experienced. Winds are strong onshore, making it a messy, challenging beast.
Thursday, August 6th, the swell peaks at 23 ft to 25 ft from the east-northeast, 19-second period. Energy is 37392 to 44233. This is a massive, dangerous swell. The wind is a near gale to severe gale, cross-onshore, and totally blown out. Honestly, this setup looks more interesting for kite surfing than paddle surfing. It’s just too big and wild for a standard board.
After that, the swell crashes down. Friday, August 7th, the wind shifts to storm force, and the swell drops to 12 ft from the north, but it’s a total mess. The rest of the second week, from August 8th to the 15th, is a long, slow decline. Swells are small (2 ft to 6 ft), periods are shorter, and the wind is mostly cross-offshore or onshore. The energy is low to moderate. There are a few clean windows, but the waves are just too small to get excited about. The best of the late run is maybe Monday, August 10th afternoon, with a 4 ft east swell and 13-second period, but the wind is moderate and cross-offshore, keeping it clean but weak.
The water temperature is sitting at 86°F, which is a touch warmer than normal for this time of year (anomaly of 2°F). That’s a nice little bonus for the skin.
Truth be told, the only real standout here is Tuesday, August 4th. That’s the day with the biggest, longest-period swell that’s still within a manageable range for strong intermediate to expert surfers. The Sunday morning, August 2nd, window is a sneaky pick for the longboard or funboard crew, thanks to the clean conditions and long period.
Overall, it’s a week of waiting, then a big pulse of energy, then a slow fade. The forecast is solid for the near-term, but the long-range stuff after August 7th is less certain. Keep an eye on Tuesday.
Rusty out.
Short Range ForecastLight rain (total 4mm), mostly falling on Mon night. Warm (max 30°C on Sun afternoon, min 28°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 41mm), heaviest during Thu night. Warm (max 30°C on Tue morning, min 29°C on Tue morning). Winds increasing (light winds from the NE on Tue morning, extremely windy from the NNE by Thu night). | ||||||||||||||||||||
Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | Wednesday 5 | Thursday 6 | Friday 7 | |||||||||||||||
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) | E 9 | E 9 | ESE 9 | E 16 | E 17 | E 16 | E 15 | E 16 | E 16 | E 18 | E 18 | E 18 | E 18 | ENE 19 | E 19 | E 19 | ENE 19 | NE 16 | ENE 15 | SSE 14 | ENE 16 |
Wave Graph | |||||||||||||||||||||
14 | 6 | 8 | 78 | 214 | 496 | 674 | 853 | 1101 | 1968 | 2436 | 3777 | 5309 | 12081 | 22452 | 40803 | 51401 | 60515 | 661 | 0 | 25 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross-on | on | cross-on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | on | on | cross |
High Tide | 8:46PM1.94m | 8:30AM1.98m | 9:13PM1.94m | 9:12AM1.92m | 9:43PM1.92m | 9:57AM1.81m | 10:16PM1.89m | 10:52AM1.67m | 10:55PM1.84m | 12:07PM1.52m | 11:45PM1.78m | 2:06PM1.45m | 00:58AM1.73m | ||||||||
Low Tide | 2:22PM0.31m | 2:36AM0.74m | 2:54PM0.40m | 3:13AM0.68m | 3:27PM0.52m | 3:54AM0.64m | 4:02PM0.68m | 4:44AM0.64m | 4:41PM0.86m | 5:46AM0.65m | 5:31PM1.05m | 7:08AM0.65m | 6:49PM1.21m | ||||||||
5:50 | — | — | 5:50 | — | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:54 | — | — | |
— | 7:15 | — | — | 7:14 | — | — | 7:13 | — | — | 7:13 | — | — | 7:12 | — | — | 7:10 | — | — | 7:09 | — | |
mm | — | — | — | — | — | — | — | — | 4 | — | 1 | 1 | — | — | 3 | 4 | 3 | 29 | 73 | 116 | 246 |
Temp °C | 29 | 29 | 29 | 29 | 30 | 29 | 29 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 29 | 29 | 29 | 29 | 29 | 29 | 29 |
Feels °C | 34 | 32 | 33 | 33 | 32 | 32 | 31 | 32 | 33 | 34 | 33 | 32 | 31 | 30 | 27 | 23 | 21 | 19 | 8 | 8 | 12 |
Swell 1 Height (m) Direction Period (s) | E 9 | E 9 | ESE 9 | E 16 | E 17 | E 16 | E 15 | E 16 | E 16 | E 18 | E 18 | E 18 | E 18 | ENE 19 | E 19 | E 19 | ENE 19 | ENE 15 | ENE 15 | — | WSW 14 |
14 | 6 | 8 | 78 | 214 | 496 | 674 | 853 | 1101 | 1968 | 2436 | 3777 | 5309 | 12081 | 22452 | 40803 | 51401 | 36004 | 661 | — | 4431 | |
Swell 2 Height (m) Direction Period (s) | SE 5 | S 8 | E 9 | ESE 9 | ENE 9 | SE 9 | E 8 | S 7 | S 7 | N 5 | S 9 | — | — | — | — | — | — | N 11 | — | — | ENE 16 |
1 | 5 | 6 | 8 | 7 | 13 | 5 | 4 | 4 | 12 | 13 | — | — | — | — | — | — | 3672 | — | — | 25 | |
Swell 3 Height (m) Direction Period (s) | S 8 | SE 9 | S 7 | E 9 | ESE 7 | S 7 | SE 9 | E 15 | SE 8 | — | — | — | — | — | — | — | — | — | — | — | — |
5 | 3 | 4 | 6 | 5 | 4 | 3 | 4 | 3 | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | ENE 8 | N 4 | N 3 | N 5 | — | — | — | NE 8 | — | NNE 8 | N 10 | NNE 11 | NE 16 | SSE 13 | SSE 14 | SSE 12 |
— | — | — | — | — | 28 | 4 | 5 | 21 | — | — | — | 284 | — | 889 | 3939 | 9999 | 60515 | 54814 | 42504 | 12405 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 931 | 926 | 1344 | 1294 | 596 | 0 | 30 | 31 | 30 | 75 | 31 | 31 | 40 | 66 | 40 | 801 | 673 | 693 | 861 | 673 | 815 |
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.











