Surf Forecasts:
Monabe Rivermouth surf forecast from 27 Aug 2026:
- Best quality surf: Monday 31 Aug, 6AM (local time) - 3ft (0.9m), 11s period, S swell with cross-offshore winds.
- Most powerful swell: Wednesday 2 Sep, 9AM (local time) - 10ft (3.0m), 11s period, SSE swell with 1,978 kJ wave energy.
- Next surfable swell (1★+): Monday 31 Aug, 6AM (local time) - 3ft (0.9m), 11s period with S 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 Monday (Aug 31) at 6AM. The primary swell is predicted to be 0.9m and 11s period with a secondary swell of 0.3m and 10s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Monabe Rivermouth in the next 16 days are 3.0m 11s and forecast to arrive on Wednesday (Sep 02) at 9AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 8s period and expected on Friday (Aug 28) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Mon 31st Aug) | 3ft (0.9m) 11s |
| Best Surf | 6AM (Mon 31st Aug) | 3ft (0.9m) 11s |
| Most Powerful | 9AM (Wed 2nd Sep) | 10ft (3.0m) 11s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Howdy, Rusty here. Let’s get straight into it. Monabe Rivermouth is looking pretty flat for a long, disappointing stretch. This spot rarely breaks, and the next 16 days don’t change that story. There’s a big gap with no real surf from now, Friday the 28th of August, right through to Sunday the 30th of August – just tiny slop and poor conditions.
Water temp is 85°F, a touch warmer than normal for this time of year.
Starting Friday the 28th: a 1.0 foot SSE swell with an 8-second period (weak energy), but it’s glassy early. Nothing worth paddling for. Saturday and Sunday the 29th and 30th get smaller and worse. Monday the 31st of August shows the best of the first week: a 3 foot SSE swell in the morning with glassy wind and moderate energy – the comment says “surfable but very ordinary.” It’s a small window before the afternoon wind turns it messy.
From the 1st of September to the 8th, the swell really pumps, hitting 6 to 15 feet from the SSE/SE, with combined energy climbing into the thousands (strong to very strong). But every session has cross-onshore or onshore wind, 12 to 19 mph, with rain or thunderstorms. The wave comment is a solid “poor” or “marginal.” On the 6th of September, you’ve got a 13 to 15 foot groundswell (period 12-13 seconds) on light onshore wind – massive power, but it’s blown out and messy. A rarely-breaking river mouth in those conditions is going to be a chaotic mess. This setup looks far better for kite surfing than paddle surfing.
The second week settles a bit. The 9th is blown out with 28-34 mph winds. The 10th and 11th of September have glassy mornings with 5 to 6 foot SSE swells (moderate energy) and a “surfable” call – cleanest waves of the whole run, but still nothing special. The 12th is similar.
No true standouts here. Your best bets are the morning of Monday the 31st of August for the first clean pulse, or the mornings of the 10th and 11th of September for clean conditions – but all are just ordinary. For a spot that rarely breaks, a run like this is pretty normal.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri night. Warm (max 29°C on Fri morning, min 24°C on Sun night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 76mm), heaviest during Mon night. Warm (max 30°C on Mon morning, min 26°C on Mon night). Winds increasing (calm on Mon morning, fresh winds from the SE by Tue afternoon). | ||||||||||||||||||||
Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | |||||||||||||||
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) | SSE 8 | E 13 | E 12 | E 12 | E 12 | E 11 | E 11 | S 7 | S 7 | S 10 | S 11 | SSE 9 | SSE 9 | SSE 10 | SSE 10 | SSE 11 | SSE 11 | SSE 11 | SSE 11 | S 10 | S 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 94 | 83 | 74 | 44 | 44 | 36 | 21 | 54 | 37 | 206 | 381 | 409 | 549 | 838 | 1196 | 1978 | 1846 | 1661 | 1905 | 1076 | 544 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-on | cross-on | glassy | cross-on | glassy | glassy | on | cross-off | glassy | cross-on | cross-off | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross |
High Tide | 6:34PM1.80m | 6:14AM1.86m | 6:56PM1.84m | 6:50AM1.86m | 7:19PM1.85m | 7:27AM1.82m | 7:43PM1.84m | 8:08AM1.74m | 8:08PM1.81m | 8:53AM1.62m | 8:36PM1.75m | 9:49AM1.48m | 9:09PM1.67m | ||||||||
Low Tide | 12:08PM0.18m | 00:21AM0.60m | 12:37PM0.21m | 00:51AM0.50m | 1:05PM0.28m | 1:22AM0.42m | 1:34PM0.40m | 1:56AM0.37m | 2:03PM0.55m | 2:34AM0.36m | 2:35PM0.72m | 3:19AM0.39m | 3:09PM0.91m | ||||||||
 |  |  | | |  | | |  | |  |  |  |  | | | | | | | | |
 | 5:35 | — | — | 5:35 | — | — | 5:35 | — | — | 5:37 | — | — | 5:37 | — | — | 5:37 | — | — | 5:39 | — | — |
 | — | 6:36 | — | — | 6:35 | — | — | 6:34 | — | — | 6:31 | — | — | 6:30 | — | — | 6:30 | — | — | 6:28 | — |
mm | — | — | 2 | — | — | — | — | — | — | — | 1 | 12 | 9 | 12 | 23 | 6 | 5 | 8 | 3 | 4 | 7 |
Temp °C | 29 | 29 | 27 | 29 | 29 | 27 | 29 | 29 | 26 | 30 | 30 | 27 | 27 | 27 | 27 | 28 | 28 | 26 | 29 | 29 | 26 |
Feels °C | 33 | 33 | 32 | 33 | 32 | 33 | 33 | 32 | 31 | 32 | 32 | 29 | 28 | 28 | 28 | 30 | 29 | 28 | 30 | 31 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 8 | S 7 | S 8 | SSW 8 | E 12 | E 11 | SSW 7 | S 7 | S 7 | S 10 | S 11 | SSE 9 | SSE 9 | SSE 10 | SSE 10 | SSE 11 | SSE 11 | SSE 11 | SSE 11 | S 10 | S 9 |
| kJ | 103 | 106 | 115 | 94 | 44 | 36 | 73 | 54 | 37 | 206 | 381 | 409 | 549 | 838 | 1196 | 1628 | 1846 | 1661 | 1905 | 1076 | 544 |
Swell 2 Height (m) Direction Period (s) | SSE 8 | E 13 | E 12 | E 12 | SSE 9 | SE 11 | SE 10 | SE 10 | SE 10 | SW 9 | SE 10 | E 14 | S 11 | E 12 | E 11 | E 12 | E 11 | E 11 | E 10 | SSW 11 | E 9 |
| kJ | 94 | 83 | 74 | 44 | 8 | 19 | 17 | 17 | 37 | 21 | 33 | 33 | 121 | 72 | 94 | 132 | 84 | 55 | 47 | 47 | 151 |
Swell 3 Height (m) Direction Period (s) | ESE 11 | SSE 8 | SE 9 | SE 10 | SSE 11 | SSE 9 | E 11 | E 11 | E 11 | SE 10 | E 11 | E 11 | E 13 | — | — | E 12 | — | — | — | E 13 | SSW 10 |
| kJ | 38 | 25 | 14 | 14 | 12 | 8 | 21 | 21 | 21 | 17 | 9 | 9 | 54 | — | — | 132 | — | — | — | 4 | 38 |
Wind waves Height (m) Direction Period (s) | SW 10 | — | — | — | SSW 7 | SSW 7 | — | — | — | — | E 5 | — | E 10 | — | — | SSE 11 | — | — | SSE 10 | E 9 | — |
| kJ | 180 | — | — | — | 91 | 97 | — | — | — | — | 1 | — | 19 | — | — | 1978 | — | — | 1508 | 160 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 42 | 42 | 9 | 42 | 9 | 9 | 42 | 9 | 0 | 490 | 0 | 531 | 531 | 528 | 462 | 638 | 50 | 20 | 50 | 20 |
Best forecast wave conditions in Shikoku | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Monabe Rivermouth surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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.
Nearest