Surf Forecasts:
Monabe Rivermouth surf forecast from 11 Aug 2026:
- Best quality surf: Wednesday 12 Aug, 12AM (local time) - 3ft (0.9m), 10s period, E swell with offshore winds.
- Most powerful swell: Sunday 16 Aug, 9PM (local time) - 4ft (1.2m), 11s period, E swell with 344 kJ wave energy.
- Next surfable swell (1★+): Wednesday 12 Aug, 12AM (local time) - 3ft (0.9m), 10s period with E swell.
Best Forecast Surf Conditions for Monabe Rivermouth this week:
The surf forecast for Monabe Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Aug 12) at 12AM. The primary swell is predicted to be 0.9m and 10s period. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Monabe Rivermouth in the next 16 days are 1.2m 11s and forecast to arrive on Sunday (Aug 16) at 9PM. Winds are predicted to be glassy at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 10s period and expected on Wednesday (Aug 12) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Wed 12th Aug) | 3ft (0.9m) 10s |
| Best Surf | 12AM (Wed 12th Aug) | 3ft (0.9m) 10s |
| Most Powerful | 9PM (Sun 16th Aug) | 4ft (1.2m) 11s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright, grab your coffee and listen up. This is Rusty. Bit of a tough one to call for Monabe Rivermouth if you're looking for a proper session right now.
Alright, straight up: the next week and a half is pretty grim. There are waves, sure, but they're mostly small, weak, and the conditions are messy. We've got a stretch from Tuesday the 11th all the way through to the Saturday the 15th that is just not worth paddling out for unless you're desperate to sit on your board and float. Wind is on it, or there are thunderstorms, or it's tiny. The combined energy is barely registering, with values down around 1ft or 2ft on some days – that’s barely a ripple. The water's running about 84°, which is a touch warmer than normal for this time of year, but that doesn't matter much when the surf is flat.
The first real flicker of hope comes Sunday the 16th morning. That's the best on offer in the whole outlook. We've got a 4ft east swell, and with a 10-second period, it's got some shape. The morning is glassy. The combined energy actually pushes into the moderate zone at 454. It's still surfable, but just ordinary. It’s a rare one for this spot, as it just doesn’t break often.
After that, it's back to slim pickings. We get another long gap of flat or poor conditions. Mind you, on Wednesday the 26th morning, there's another chance – a glassy morning with a 4ft swell from the southeast that might offer a small rip at dawn, but the afternoon gets messy with a cross-onshore wind and a much bigger 6ft swell that is poor quality. That 6ft in the afternoon looks a bit more interesting for kiteboarding than proper surfing due to the side-wind, not for us paddling.
So, to be honest, the standout session is Sunday the 16th morning. It's not perfect, but it's the cleanest window in a long run of junk. If I had to pick one, I'd be there at dawn on the 16th. The rest of the time, leave the board in the car.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Thu night. Warm (max 29°C on Tue afternoon, min 22°C on Tue night). Wind will be generally light. | Days 5-7 Weather SummarySome drizzle, heaviest during Sat night. Warm (max 28°C on Fri afternoon, min 23°C on Fri night). Wind will be generally light. | |||||||||||||||||||
Tue 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | ||||||||||||||
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 11 | E 10 | E 11 | S 10 | E 10 | E 10 | E 10 | E 9 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 11 | E 11 | E 10 | SE 11 |
Wave Graph  | ||||||||||||||||||||
 kJ | 286 | 177 | 116 | 94 | 32 | 30 | 28 | 43 | 71 | 78 | 94 | 100 | 94 | 91 | 290 | 290 | 342 | 144 | 76 | 30 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | off | cross-off | cross-on | cross-off | cross-on | on | glassy | glassy | on | cross-off | glassy | on | off | glassy | on | glassy | glassy | cross-on | cross-off |
High Tide | 5:54PM1.79m | 4:53AM1.82m | 6:28PM1.85m | 5:42AM1.90m | 6:59PM1.87m | 6:27AM1.93m | 7:27PM1.86m | 7:10AM1.89m | 7:54PM1.84m | 7:51AM1.81m | 8:19PM1.79m | 8:33AM1.68m | 8:43PM1.73m | |||||||
Low Tide | 11:23PM0.92m | 11:43AM-0.03m | 00:02AM0.79m | 12:23PM-0.02m | 00:40AM0.67m | 1:00PM0.06m | 1:16AM0.57m | 1:33PM0.19m | 1:52AM0.51m | 2:04PM0.37m | 2:28AM0.48m | 2:33PM0.56m | ||||||||
 |  | |  |  | |  |  | | | | | |  | | |  | | | | |
 | — | — | 5:24 | — | — | 5:24 | — | — | 5:24 | — | — | 5:26 | — | — | 5:26 | — | — | 5:26 | — | — |
 | 6:55 | — | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:49 | — |
mm | — | — | — | — | — | — | 2 | 3 | — | — | — | — | — | 1 | — | — | — | — | — | — |
Temp °C | 29 | 24 | 28 | 27 | 26 | 28 | 27 | 25 | 28 | 28 | 25 | 28 | 28 | 25 | 28 | 28 | 26 | 27 | 27 | 26 |
Feels °C | 31 | 24 | 29 | 29 | 29 | 28 | 29 | 28 | 30 | 30 | 29 | 30 | 31 | 29 | 31 | 31 | 31 | 32 | 31 | 31 |
Swell 1 Height (m) Direction Period (s) | SSW 10 | SSW 10 | SSW 10 | SSW 10 | SSW 10 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SSW 9 | SSW 8 | SSW 10 | SSW 9 | E 6 | E 10 | E 10 | E 11 | E 11 | SSW 8 | SSW 8 |
| kJ | 265 | 270 | 246 | 114 | 201 | 141 | 110 | 106 | 99 | 77 | 94 | 157 | 110 | 91 | 290 | 290 | 342 | 144 | 55 | 54 |
Swell 2 Height (m) Direction Period (s) | E 11 | E 10 | E 11 | S 10 | E 10 | E 10 | E 10 | E 9 | E 10 | E 10 | E 10 | E 10 | E 10 | SSW 9 | S 10 | SSW 9 | SSW 8 | SSW 8 | E 10 | E 10 |
| kJ | 286 | 177 | 116 | 94 | 32 | 30 | 28 | 43 | 71 | 78 | 94 | 100 | 94 | 99 | 115 | 82 | 75 | 75 | 76 | 30 |
Swell 3 Height (m) Direction Period (s) | SE 13 | SE 13 | S 10 | E 11 | SE 12 | SE 12 | ESE 3 | SE 12 | E 5 | SE 11 | E 4 | SE 10 | ESE 8 | E 10 | SE 12 | SE 11 | SE 11 | SE 11 | SE 11 | SE 11 |
| kJ | 27 | 27 | 31 | 56 | 24 | 23 | 2 | 21 | 4 | 19 | 6 | 47 | 47 | 90 | 49 | 45 | 42 | 30 | 30 | 30 |
Wind waves Height (m) Direction Period (s) | NE 6 | — | N 3 | — | — | — | — | — | — | E 4 | — | — | E 5 | — | — | — | — | WSW 3 | — | SW 3 |
| kJ | 75 | — | 1 | — | — | — | — | — | — | 9 | — | — | 26 | — | — | — | — | 1 | — | 1 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 426 | 0 | 9 | 50 | 9 | 20 | 559 | 9 | 9 | 50 | 9 | 9 | 335 | 9 | 0 | 42 | 0 | 9 | 42 | 9 |
Best forecast wave conditions in Shikoku | ||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||
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Information about the Monabe Rivermouth Surf forecast
The above surf forecast table for Monabe Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Monabe Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Monabe 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 (Monabe 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 Monabe 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.
Monabe Rivermouth is 11 km (7 miles) from the city of Aki. If you plan a holiday in Shikoku, look for hotels and other accommodation in Aki. Aki has rooms for a wide range of budgets as well as car hire and transport links.
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