Surf Forecasts:
Aha Rivermouth surf forecast from 11 Sep 2026:
- Most powerful swell: Saturday 19 Sep, 3AM (local time) - 5ft (1.6m), 17s period, E swell with 1,456 kJ wave energy.
Best Forecast Surf Conditions for Aha Rivermouth this week:
The most powerful waves expected at Aha Rivermouth in the next 16 days are 1.6m 17s and forecast to arrive on Saturday (Sep 19) at 3AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 8s period and expected on Saturday (Sep 19) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 3AM (Sat 19th Sep) | 5ft (1.6m) 17s |
Table - best surf conditions forecast for Aha Rivermouth over the next 16 days.
The Lowdown
Alright, this is Rusty. Let’s have a look at what’s cookin’ over the next couple weeks.
Honestly, it’s a pretty bleak run for Aha Rivermouth. There’s a real ugly gap of surf that’s just not worth paddling out for right up until the middle of the second week. For days and days, it’s cross-onshore junk, choppy, and the kind of stuff that’ll make you question your life choices. The combined swell energy is mostly in the moderate range, around 166 (Sunday 12th) to 270 (Monday 14th), but with that wind and short period, it’s all mush. The water temp is about average for this time of year. Then on Saturday the 19th, things go proper mental – swell jumps to 8 ft and then 13 ft with a long 18-second period, but the energy skyrockets to 9864. It’s huge, but with 22 mph cross-onshore winds, it’s a total blown-out mess, only for the absolute nutters and even then, it’s not clean. By Sunday the 20th, we’re talking 16 ft and 34-47 mph winds – that’s a no-go zone, more like a storm-watching session than a surf.
The only real standout in this whole outlook lands on Tuesday the 22nd. It’s a proper brute of a day. We’ve got a 10 ft swell from the N, with a 13-second period, and the combined energy is a massive 3564. The wind is cross-off from the W at 25 mph, which is clean and offshore, and the forecast even says wind and tide are favorable. That said, the swell is well over 8 ft, so this is expert-only territory – not for the faint of heart, especially at a beach/jetty setup. If you’re a charger, that Tuesday arvo is the one clear window where everything lines up, albeit for the brave.
Before that, you’ve got nothing worth your time. Monday the 21st has 13 ft from the NNW and clean cross-off wind, but the energy is huge (4847), and it’s still too raw and big with that violent storm wind – it’s more interesting for a kite surfer than a paddle surfer. After Tuesday, it drops off again into a mix of choppy, cross-onshore junk and big, lumpy leftovers that aren’t worth chasing.
So, to sum it up: the first week is a total bust. The best – and really the only – bet is that Tuesday the 22nd afternoon session for experts only. It’s a short window, but if you’ve got the stones and a big board, that’s your shot.
Rusty
Short Range ForecastModerate rain (total 12mm), heaviest on Sun night. Warm (max 28°C on Fri night, min 27°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 28mm), heaviest during Mon night. Warm (max 28°C on Mon night, min 27°C on Mon night). Wind will be generally light. | ||||||||||||||||||
Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | ||||||||||||||
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 14 | E 14 | E 14 | E 14 | E 14 | E 8 | E 8 | E 8 | E 9 | E 9 | E 9 | E 9 | E 10 | E 10 | E 9 | ENE 14 | E 9 | ENE 13 | E 9 |
Wave Graph  | |||||||||||||||||||
 kJ | 64 | 101 | 103 | 103 | 97 | 159 | 182 | 177 | 177 | 220 | 194 | 211 | 183 | 179 | 140 | 160 | 139 | 135 | 133 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | on | cross-on | cross-on | on | cross-on | cross-on | on | cross-on | cross-on | on | cross-on |
High Tide | 7:09AM2.12m | 7:28PM2.07m | 7:44AM2.08m | 7:53PM2.07m | 8:19AM1.99m | 8:18PM2.05m | 8:53AM1.87m | 8:43PM1.99m | 9:28AM1.73m | 9:07PM1.91m | 10:07AM1.57m | 9:31PM1.81m | |||||||
Low Tide | 1:04AM0.46m | 1:22PM0.37m | 1:36AM0.38m | 1:50PM0.46m | 2:09AM0.35m | 2:16PM0.58m | 2:41AM0.37m | 2:41PM0.71m | 3:14AM0.43m | 3:04PM0.85m | 3:49AM0.52m | 3:26PM0.99m | |||||||
 |  |  |  | |  | | | |  | | | | | | | | |  | |
 | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — |
 | 6:36 | — | 6:35 | — | — | 6:34 | — | — | 6:32 | — | — | 6:31 | — | — | 6:30 | — | — | 6:30 | — |
mm | 4 | — | — | — | — | 2 | 5 | 1 | — | 10 | 7 | 2 | 1 | 1 | 4 | 2 | 1 | — | — |
Temp °C | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
Feels °C | 31 | 31 | 30 | 30 | 29 | 29 | 30 | 30 | 30 | 30 | 32 | 30 | 30 | 31 | 30 | 30 | 32 | 30 | 30 |
Swell 1 Height (m) Direction Period (s) | N 7 | SE 6 | N 7 | E 14 | E 14 | E 14 | E 13 | E 8 | E 9 | E 13 | E 9 | E 9 | E 10 | E 10 | E 9 | E 9 | E 9 | E 9 | E 9 |
| kJ | 40 | 29 | 34 | 103 | 97 | 101 | 92 | 177 | 177 | 87 | 194 | 211 | 183 | 179 | 140 | 139 | 139 | 103 | 127 |
Swell 2 Height (m) Direction Period (s) | ENE 14 | N 7 | E 14 | N 6 | ESE 9 | N 6 | N 5 | E 13 | E 13 | S 6 | E 12 | E 12 | ENE 12 | ENE 14 | ENE 14 | ENE 14 | ENE 13 | ENE 13 | ENE 13 |
| kJ | 64 | 36 | 103 | 20 | 28 | 6 | 12 | 89 | 87 | 1 | 78 | 76 | 50 | 145 | 105 | 160 | 137 | 135 | 133 |
Swell 3 Height (m) Direction Period (s) | S 7 | E 14 | S 7 | S 7 | NNW 6 | S 6 | S 6 | N 5 | N 5 | — | S 6 | NNW 6 | NNW 5 | NNW 6 | NNW 6 | N 6 | N 6 | NNW 6 | NNW 6 |
| kJ | 8 | 101 | 8 | 8 | 12 | 3 | 3 | 4 | 2 | — | 1 | 4 | 3 | 17 | 23 | 12 | 7 | 11 | 11 |
Wind waves Height (m) Direction Period (s) | SE 6 | — | SE 6 | ESE 5 | ESE 6 | E 8 | E 8 | — | — | E 9 | — | — | — | — | — | — | — | — | — |
| kJ | 39 | — | 26 | 27 | 52 | 159 | 182 | — | — | 220 | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 12 | 44 | 60 | 70 | 70 | 70 | 70 | 595 | 66 | 70 | 12 | 40 | 40 | 12 | 40 | 40 | 12 | 40 | 70 |
Best forecast wave conditions in Okinawa | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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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