Surf Forecasts:
Monabe Rivermouth surf forecast from 7 Sep 2026:
- Best quality surf: Wednesday 9 Sep, 12AM (local time) - 7.5ft (2.3m), 9s period, SSE swell with cross-offshore winds.
- Most powerful swell: Wednesday 9 Sep, 3AM (local time) - 8ft (2.5m), 9s period, SSE swell with 1,079 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 6PM (local time) - 5ft (1.6m), 9s period with SE 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 (Sep 07) at 6PM. The primary swell is predicted to be 1.6m and 9s period with a secondary swell of 0.7m and 10s. Another secondary swell of 1.0m and 8s is also forecast. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Monabe Rivermouth in the next 16 days are 2.5m 9s and forecast to arrive on Wednesday (Sep 09) at 3AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 6s period and expected on Thursday (Sep 10) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Mon 7th Sep) | 5ft (1.6m) 9s |
| Best Surf | 12AM (Wed 9th Sep) | 7.5ft (2.3m) 9s |
| Most Powerful | 3AM (Wed 9th Sep) | 8ft (2.5m) 9s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s have a look at what’s on offer for Monabe Rivermouth over the next couple of weeks.
First up, the water temp is sitting at a balmy 85°, which is about 4° warmer than normal for this time of year. That’s properly warm – more like a tropical bath than your usual September.
The pattern for this 16-day run is pretty quiet overall. There are no real standout days that will get your heart racing. The first rideable surf doesn’t show up until Monday 7th September, with a 4ft swell from the ESE at 9 seconds. The energy is moderate (636). It’s clean in the morning with a light northerly offshore at 3 mph, but it’s very ordinary, inconsistent, and rarely breaks here. Monday afternoon goes onshore and turns poor.
Tuesday 8th September offers a similar story: 5ft from the south, 9 seconds, with glassy conditions through both sessions. The energy is still moderate (544-598), but it remains “surfable but very ordinary.” Wednesday 9th September bumps up a touch to 7ft on the SSE swell (688 energy) and clean morning northerly offshore at 6 mph. That’s the biggest wave height of the run, but it’s nothing special, and the break is so sheltered and inconsistent that it rarely delivers.
From Thursday 10th September onward, the swell drops off into the 2ft to 5ft range with mostly low energy readings (between 50 and 454). Winds are often glassy or light offshore, but the quality is poor to ordinary at best. A few sessions, like Tuesday 15th morning, show 5ft from the ESE with glassy conditions and moderate energy (365), but again, it’s nothing to write home about.
The second week (from around 14th September) is even quieter. Most days have weak energy, with readings dropping below 100 by the 18th. There’s a small pulse on the morning of Sunday 20th September with 4ft from the ENE (379 energy) and a light cross-offshore, but it’s still just “surfable” – no punch.
Honestly, for a spot that rarely breaks and is very sheltered, this is a pretty typical flat spell. Not much for the surfer here unless you’re desperate for a splash in warm water. The best shot would be the morning of Wednesday 9th September if you’re local and just want to get wet for a small, clean wave – 7ft from the SSE with a light offshore. But for a real standout? There isn’t one.
Signing off – Rusty.
Short Range ForecastHeavy rain (total 102mm), heaviest during Tue night. Warm (max 28°C on Tue morning, min 24°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 20mm), heaviest during Thu afternoon. Warm (max 28°C on Sat afternoon, min 23°C on Thu afternoon). Wind will be generally light. | ||||||||||||||||||||
Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | |||||||||||||||
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) | ESE 9 | ESE 9 | SE 8 | S 9 | S 9 | SSE 9 | SSE 9 | SSE 8 | SE 8 | SSE 9 | SE 8 | SSE 8 | SSE 7 | SSE 7 | SSE 7 | E 13 | E 14 | E 14 | E 13 | ESE 13 | ESE 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 288 | 553 | 250 | 332 | 332 | 898 | 676 | 374 | 129 | 103 | 164 | 117 | 84 | 74 | 63 | 88 | 89 | 192 | 85 | 317 | 161 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | on | glassy | glassy | glassy | cross-off | off | off | off | off | glassy | glassy | glassy | glassy | cross | glassy | on | cross-off | glassy | on | off |
High Tide | 4:23PM1.60m | 3:00AM1.57m | 4:57PM1.71m | 4:03AM1.71m | 5:26PM1.79m | 4:52AM1.83m | 5:53PM1.84m | 5:36AM1.91m | 6:18PM1.86m | 6:17AM1.93m | 6:43PM1.87m | 6:55AM1.89m | 7:06PM1.85m | ||||||||
Low Tide | 9:02AM0.35m | 9:49PM1.08m | 10:00AM0.23m | 10:32PM0.91m | 10:46AM0.15m | 11:08PM0.74m | 11:25AM0.13m | 11:42PM0.58m | 12:00PM0.17m | 00:14AM0.45m | 12:32PM0.26m | 00:46AM0.35m | 1:01PM0.39m | 1:18AM0.30m | |||||||
 |  |  | |  |  |  | |  |  |  |  | | | | |  |  | | | | |
 | 5:41 | — | — | 5:41 | — | — | 5:43 | — | — | 5:43 | — | — | 5:43 | — | — | 5:45 | — | — | 5:46 | — | — |
 | — | 6:22 | — | — | 6:22 | — | — | 6:20 | — | — | 6:19 | — | — | 6:17 | — | — | 6:15 | — | — | 6:15 | — |
mm | 2 | — | — | 1 | 2 | 74 | 22 | — | 1 | 1 | 7 | 2 | 2 | 4 | 3 | 1 | — | — | — | 1 | 2 |
Temp °C | 27 | 27 | 26 | 28 | 28 | 26 | 26 | 28 | 25 | 25 | 24 | 24 | 26 | 27 | 26 | 27 | 28 | 25 | 28 | 28 | 25 |
Feels °C | 31 | 31 | 30 | 32 | 33 | 31 | 29 | 31 | 28 | 27 | 28 | 29 | 31 | 32 | 31 | 31 | 33 | 30 | 31 | 32 | 29 |
Swell 1 Height (m) Direction Period (s) | ESE 9 | ESE 9 | SE 8 | S 9 | S 9 | SSE 9 | SSE 9 | SSE 8 | SE 8 | ENE 5 | SE 8 | SSE 8 | SSE 7 | SSE 7 | SSE 7 | S 7 | S 7 | E 14 | ESE 9 | ESE 13 | ESE 9 |
| kJ | 288 | 553 | 250 | 332 | 332 | 898 | 676 | 374 | 129 | 46 | 164 | 117 | 84 | 74 | 62 | 47 | 37 | 192 | 48 | 317 | 161 |
Swell 2 Height (m) Direction Period (s) | E 8 | S 11 | S 10 | ESE 8 | ESE 10 | E 19 | E 18 | E 18 | S 8 | SSE 9 | E 15 | E 15 | E 7 | E 14 | E 14 | E 13 | E 14 | S 7 | S 7 | S 11 | S 10 |
| kJ | 195 | 83 | 196 | 172 | 40 | 7 | 6 | 6 | 37 | 103 | 17 | 38 | 60 | 60 | 63 | 88 | 89 | 36 | 24 | 114 | 133 |
Swell 3 Height (m) Direction Period (s) | SSE 9 | SW 10 | SSW 11 | ESE 10 | ESE 10 | — | E 18 | W 6 | E 7 | SE 7 | E 17 | SE 11 | SSW 8 | ESE 10 | ESE 10 | ESE 10 | ESE 10 | S 8 | E 13 | S 7 | E 13 |
| kJ | 153 | 24 | 101 | 40 | 40 | — | 6 | 1 | 15 | 34 | 23 | 5 | 11 | 19 | 18 | 19 | 38 | 1 | 85 | 23 | 82 |
Wind waves Height (m) Direction Period (s) | NNE 5 | ENE 5 | ENE 5 | NE 4 | ESE 8 | NE 4 | — | NE 3 | ENE 6 | NE 6 | NE 5 | E 6 | ENE 7 | E 4 | ENE 6 | E 5 | E 4 | — | — | — | — |
| kJ | 51 | 69 | 46 | 21 | 186 | 25 | — | 7 | 46 | 103 | 12 | 48 | 79 | 18 | 12 | 12 | 10 | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 9 | 0 | 0 | 0 | 0 | 0 | 0 | 9 | 9 | 0 | 0 | 0 | 9 | 20 | 9 | 50 | 0 | 9 | 75 | 0 |
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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