
Surf Forecasts:
Monabe Rivermouth surf forecast from 9 Jul 2026:
- Best quality surf: Saturday 11 Jul, 12AM (local time) - 15ft (4.5m), 17s period, S swell with cross-offshore winds.
- Most powerful swell: Saturday 11 Jul, 6AM (local time) - 16ft (5.0m), 18s period, S swell with 13,649 kJ wave energy.
- Next surfable swell (1★+): Thursday 9 Jul, 6PM (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 Thursday (Jul 09) at 6PM. The primary swell is predicted to be 3.0m and 15s period with a secondary swell of 0.5m and 8s. 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 5.0m 18s and forecast to arrive on Saturday (Jul 11) at 6AM. Winds are predicted to be glassy at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 5.0m 18s period and expected on Saturday (Jul 11) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Thu 9th Jul) | 10ft (3.0m) 15s |
| Best Surf | 12AM (Sat 11th Jul) | 15ft (4.5m) 17s |
| Most Powerful | 6AM (Sat 11th Jul) | 16ft (5.0m) 18s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
Alright folks, Rusty here. Let’s get into it.
First up, we’ve got Monabe Rivermouth. This is a river mouth setup that only rarely breaks, so we need to be patient. The water temperature is sitting at 77°, which is a bit colder than normal for this time of year – about 3° cooler than average, so you’ll feel that difference.
The pattern kicks off on Thursday, 9th July with a solid 10ft swell from the SSE, but it’s blown out by onshore winds. The swell energy is pumping (3403), but the conditions are marginal, and the tide’s likely an issue. Not the day.
Friday, 10th July morning is the standout of the entire forecast period. We’ve got a 13ft swell from the S, with a long 17-second period – that’s proper groundswell energy. The wind goes glassy, and the combined energy is massive (7851). This is a big, powerful wave. Over 8ft, so this is for experienced surfers only. The long period means the river mouth setup could be a bit tricky, but if the tide plays ball, it’ll be a proper session. The afternoon stays onshore, so get it early.
After that, it drops off hard. From Saturday, 11th July through to the end of the week, we’re looking at flat to tiny waves – nothing over 3ft until the following week. The swell energy stays below 100 for days, and most of it is poor surf conditions. There’s a long gap of about 8 days with hardly anything worth paddling out for.
Things start to look up again on Sunday, 19th July morning. The swell builds to 6ft from the ESE, with a 13-second period, and it’s glassy. The combined energy is 950 – moderate, but the conditions are clean. The afternoon gets onshore, so morning is the go.
Monday, 20th July morning is another one to circle. Swell jumps to 8ft from the SE, 14-second period, glassy winds, and the energy is strong (2414). This is getting big again, into the expert-only zone, but the river mouth could handle it.
From Tuesday, 21st July onwards, the swell stays big – 12ft to 13ft – but the winds turn cross-on or onshore, and the quality drops. The period drops to 12-13 seconds, and the conditions are marked as marginal. The last real hope is Friday, 24th July morning, with a 7ft SSE swell, 12-second period, and glassy conditions. The energy is moderate (1442), and it’s a clean option for the end of the run.
Overall, this is a classic case of a rare break that fires for one morning, then goes quiet for over a week, then offers a few more solid but tricky days. The only true standout is Friday, 10th July morning – get it while it’s there.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Fri morning, min 22°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 10mm), heaviest on Sun night. Warm (max 28°C on Sun morning, min 25°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Thursday 9 | Friday 10 | Saturday 11 | Sunday 12 | Monday 13 | Tuesday 14 | Wednesday 15 | |||||||||||||||
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 15 | SSE 15 | SSE 16 | S 17 | S 17 | S 17 | S 18 | SSW 18 | SSW 17 | SSW 16 | SE 11 | E 9 | SE 10 | SE 10 | SE 10 | E 9 | E 9 | E 9 | E 10 | E 10 | ESE 9 |
Wave Graph | |||||||||||||||||||||
3319 | 3247 | 4541 | 7851 | 7598 | 12170 | 0 | 0 | 0 | 0 | 19 | 27 | 17 | 17 | 16 | 25 | 25 | 43 | 47 | 47 | 65 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-off | glassy | on | cross-off | glassy | on | glassy | glassy | glassy | off | glassy | on | glassy | glassy | on | glassy | glassy | cross-on | off |
High Tide | 1:23PM1.36m | 00:42AM1.59m | 3:02PM1.45m | 1:48AM1.61m | 4:18PM1.58m | 2:54AM1.66m | 5:16PM1.70m | 3:56AM1.73m | 6:05PM1.79m | 4:52AM1.81m | 6:48PM1.85m | 5:43AM1.87m | 7:28PM1.86m | ||||||||
Low Tide | 6:35PM0.98m | 7:58AM0.45m | 8:06PM1.07m | 9:06AM0.29m | 9:29PM1.09m | 10:07AM0.13m | 10:35PM1.06m | 11:01AM-0.00m | 11:28PM1.00m | 11:51AM-0.09m | 00:14AM0.93m | 12:37PM-0.11m | 00:58AM0.86m | ||||||||
5:01 | — | — | 5:01 | — | — | 5:01 | — | — | 5:03 | — | — | 5:03 | — | — | 5:03 | — | — | 5:05 | — | — | |
— | 7:16 | — | — | 7:16 | — | — | 7:16 | — | — | 7:16 | — | — | 7:15 | — | — | 7:15 | — | — | 7:15 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | 8 | — | 2 | — | — | — | — | — | — | — |
Temp °C | 26 | 26 | 24 | 27 | 27 | 25 | 27 | 27 | 25 | 28 | 27 | 25 | 28 | 28 | 26 | 28 | 27 | 25 | 27 | 27 | 25 |
Feels °C | 29 | 29 | 28 | 31 | 31 | 30 | 30 | 31 | 30 | 32 | 32 | 30 | 32 | 33 | 30 | 32 | 31 | 30 | 31 | 31 | 30 |
Swell 1 Height (m) Direction Period (s) | SSE 15 | SSE 15 | SSE 16 | S 17 | S 17 | S 17 | S 18 | SSW 18 | SSW 17 | SSW 16 | SSW 14 | SSW 13 | SSW 12 | SSW 11 | SSW 11 | SSW 10 | SSW 10 | SSW 9 | SSW 9 | SSW 9 | ESE 9 |
3319 | 3247 | 4541 | 7851 | 7598 | 12170 | 13751 | 14129 | 13052 | 6203 | 3203 | 1671 | 969 | 681 | 485 | 255 | 209 | 121 | 84 | 79 | 65 | |
Swell 2 Height (m) Direction Period (s) | E 8 | S 19 | S 21 | — | S 20 | — | — | — | — | — | E 9 | E 9 | E 9 | E 9 | E 8 | E 9 | E 9 | E 9 | E 10 | E 10 | SSW 8 |
84 | 715 | 1035 | — | 1835 | — | — | — | — | — | 15 | 27 | 15 | 14 | 12 | 25 | 25 | 43 | 47 | 47 | 54 | |
Swell 3 Height (m) Direction Period (s) | — | E 8 | E 8 | — | — | — | — | — | — | — | SE 11 | E 9 | SE 10 | SE 10 | SE 10 | SE 10 | SE 12 | SE 12 | SE 10 | SE 10 | SE 10 |
— | 32 | 22 | — | — | — | — | — | — | — | 19 | 15 | 17 | 17 | 16 | 15 | 22 | 21 | 16 | 16 | 16 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | NE 3 | — | — | — | — | — |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 75 | 50 | 0 | 0 | 50 | 0 | 20 | 42 | 20 | 42 | 42 | 9 | 9 | 20 | 9 | 9 | 75 | 9 | 9 | 75 | 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.










