Surf Forecasts:
Monabe Rivermouth surf forecast from 24 Aug 2026:
- Best quality surf: Tuesday 25 Aug, 6AM (local time) - 10ft (3.0m), 15s period, SSE swell with cross-offshore winds.
- Most powerful swell: Tuesday 25 Aug, 9AM (local time) - 11ft (3.5m), 15s period, SSE swell with 4,581 kJ wave energy.
- Next surfable swell (1★+): Tuesday 25 Aug, 6AM (local time) - 10ft (3.0m), 15s period with SSE 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 Tuesday (Aug 25) at 6AM. The primary swell is predicted to be 3.0m and 15s period with a secondary swell of 1.3m and 19s. 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 3.5m 15s and forecast to arrive on Tuesday (Aug 25) at 9AM. Winds are predicted to be glassy at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.1m 12s period and expected on Wednesday (Aug 26) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Tue 25th Aug) | 10ft (3.0m) 15s |
| Best Surf | 6AM (Tue 25th Aug) | 10ft (3.0m) 15s |
| Most Powerful | 9AM (Tue 25th Aug) | 11ft (3.5m) 15s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here, talkin' about the same stretch of coast. Let's break it down.
This spot is Monabe Rivermouth, a river mouth that *rarely breaks*, so it's a real treat when it turns on. Water temp is standard for the season, no big surprises.
The fireworks start on Tuesday, August 25th. We're lookin' at a solid 12ft swell from the SSE, with a super long 15-second period. That's proper groundswell, and the combined energy is a massive 4727 – that's pumping. The wind is glassy, dead calm, so the surface will be silky. This is excellent surf, but at 12ft, it's for experts only. That long period will wrap around the river mouth nicely. The afternoon is just as clean, with the swell holding at 12ft from the SSE and a 14-second period.
Wednesday, August 26th morning is still a beauty. The swell drops to 8ft from the S, with a 13-second period, and the wind is glassy. It's a clean, powerful wave for experienced surfers, with a combined energy of 2140. The crowd here can get thick sometimes, so be sharp.
From Thursday, August 27th afternoon, it all dies off. A few small, weak waves show up, but the wind turns onshore and it's a mess. You're lookin' at a solid 5-day stretch of flat, poor conditions.
There's a little bump on September 1st with a 7ft S swell, but the wind is cross-shore – not worth the hassle.
Then the big one. Sunday, September 6th morning fires up. A massive 12ft SSE swell with a very long 14-second period, and a light cross-offshore breeze. That's clean, powerful, and a combined energy of 4653. This is expert-only, no question. The afternoon gets messy, but that morning is a gem.
Monday, September 7th is still a great day. The morning has a 10ft SSE swell with an 11-second period and clean cross-offshore wind. The afternoon glassed off with a 7ft SE swell. That's a solid, fun day.
The rest of the window fades out to small waves.
The true standouts? Tuesday, August 25th morning and Sunday, September 6th morning. Both are for the big-wave crew, but the conditions are about as good as it gets. The second one is a way off, so don't bank on it just yet.
Rusty.
Short Range ForecastMostly dry. Warm (max 30°C on Wed morning, min 25°C on Mon night). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 16mm), heaviest on Fri afternoon. Warm (max 29°C on Fri morning, min 25°C on Fri night). Wind will be generally light. | ||||||||||||||||||
Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | ||||||||||||||
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 16 | SSE 15 | SSE 14 | SSE 14 | S 13 | SE 9 | SSE 8 | SSE 9 | SSE 10 | S 9 | S 8 | S 8 | E 12 | E 12 | E 12 | E 11 | E 11 | E 11 | S 8 |
Wave Graph  | |||||||||||||||||||
 kJ | 4844 | 4581 | 4099 | 3181 | 1834 | 211 | 188 | 172 | 172 | 313 | 219 | 138 | 74 | 44 | 44 | 37 | 22 | 21 | 64 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | glassy | glassy | off | glassy | on | glassy | glassy | on | glassy | glassy | cross-on | glassy | glassy | cross-on | glassy | glassy | on | glassy |
High Tide | 3:40AM1.52m | 5:30PM1.61m | 4:25AM1.63m | 5:51PM1.69m | 5:03AM1.74m | 6:12PM1.76m | 5:39AM1.81m | 6:34PM1.80m | 6:14AM1.86m | 6:56PM1.84m | 6:50AM1.86m | 7:19PM1.85m | |||||||
Low Tide | 10:30PM1.08m | 10:37AM0.35m | 10:58PM0.96m | 11:10AM0.25m | 11:25PM0.84m | 11:40AM0.20m | 11:53PM0.72m | 12:08PM0.18m | 00:21AM0.60m | 12:37PM0.21m | 00:51AM0.50m | 1:05PM0.28m | 1:22AM0.42m | ||||||
 |  | | | |  |  |  | |  |  | |  | | | |  | | | |
 | — | 5:33 | — | — | 5:33 | — | — | 5:33 | — | — | 5:35 | — | — | 5:35 | — | — | 5:35 | — | — |
 | 6:40 | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:36 | — | — | 6:35 | — | — | 6:34 | — |
mm | — | — | — | — | — | — | — | — | — | 3 | 2 | 4 | 2 | — | 2 | 1 | 1 | 1 | 3 |
Temp °C | 27 | 29 | 29 | 26 | 30 | 30 | 28 | 29 | 29 | 27 | 29 | 28 | 26 | 29 | 29 | 27 | 29 | 29 | 27 |
Feels °C | 33 | 31 | 33 | 30 | 35 | 33 | 34 | 34 | 33 | 32 | 33 | 33 | 31 | 33 | 34 | 33 | 33 | 34 | 33 |
Swell 1 Height (m) Direction Period (s) | SSE 16 | SSE 15 | SSE 14 | SSE 14 | S 13 | S 12 | SSW 12 | SSW 11 | SSW 10 | SSW 9 | S 8 | S 8 | SSW 8 | S 8 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | S 8 |
| kJ | 4844 | 4581 | 4099 | 3181 | 1834 | 1155 | 923 | 571 | 320 | 199 | 219 | 138 | 75 | 127 | 130 | 113 | 83 | 94 | 64 |
Swell 2 Height (m) Direction Period (s) | E 16 | E 15 | E 14 | E 14 | SE 9 | SE 9 | SSE 8 | SSE 9 | SSE 10 | SSE 9 | SW 12 | SSW 9 | SSE 7 | E 12 | E 12 | E 11 | SW 9 | SE 10 | SE 10 |
| kJ | 20 | 107 | 66 | 129 | 222 | 211 | 188 | 172 | 172 | 180 | 86 | 53 | 41 | 44 | 44 | 37 | 22 | 17 | 17 |
Swell 3 Height (m) Direction Period (s) | SW 8 | E 15 | E 11 | E 14 | E 13 | E 13 | E 12 | E 12 | E 12 | ESE 11 | SSW 8 | E 13 | E 12 | SW 11 | SW 10 | SE 11 | E 11 | E 11 | E 11 |
| kJ | 16 | 39 | 36 | 129 | 84 | 82 | 73 | 44 | 42 | 40 | 27 | 83 | 74 | 20 | 17 | 19 | 22 | 21 | 21 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | S 9 | — | — | — | — | — | — | WSW 3 | — | — |
| kJ | — | — | — | — | — | — | — | — | — | 313 | — | — | — | — | — | — | 5 | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 0 | 0 | 0 | 0 | 42 | 0 | 0 | 42 | 0 | 0 | 42 | 9 | 9 | 42 | 9 | 9 | 42 | 9 |
Best forecast wave conditions in Shikoku | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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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