
Surf Forecasts:
Monabe Rivermouth surf forecast from 5 Aug 2026:
- Best quality surf: Wednesday 5 Aug, 9PM (local time) - 16ft (5.0m), 16s period, SE swell with cross-offshore winds.
- Most powerful swell: Friday 7 Aug, 12AM (local time) - 18ft (5.5m), 16s period, SSE swell with 15,580 kJ wave energy.
- Next surfable swell (1★+): Wednesday 5 Aug, 9PM (local time) - 16ft (5.0m), 16s 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 Wednesday (Aug 05) at 9PM. The primary swell is predicted to be 5.0m and 16s period. 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 5.5m 16s and forecast to arrive on Friday (Aug 07) at 12AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 3.5m 14s period and expected on Saturday (Aug 08) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Wed 5th Aug) | 16ft (5.0m) 16s |
| Best Surf | 9PM (Wed 5th Aug) | 16ft (5.0m) 16s |
| Most Powerful | 12AM (Fri 7th Aug) | 18ft (5.5m) 16s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's get real about the next couple of weeks. The ocean is looking pretty dull for our stretch, and I'm not gonna lie to you. There's a big ol' dry spell comin' our way, so don't get your hopes up too high.
Right off the bat, we've got one window that looks wild on paper, but you gotta know what you're doing. On Wednesday the 5th, early morning, there's some serious size. We're talkin' 15ft of east-southeast swell, with a long 16-second period, pushing a massive amount of energy – the energy reading is a huge 11232. That's a lot of moving water. The wind is dead glassy from the south, and the water is a touch warmer than usual at 85°. It's gonna be a heavy, powerful river-mouth wave at Monabe Rivermouth. This is not for the faint of heart. At this size, it's strictly for the experienced crew. The period is so long it might be breaking a bit straight, but the rivermouth should still have some shape. It's promising, but very much a big-wave, expert-only session.
The good news doesn't last. By Wednesday afternoon, the wind swings onshore and things get choppy. That's your window. The rest of the week is a write-off. Thursday and Friday see the swell stick around at 16ft plus, but the cross-shore winds are gonna make a mess of it. It'll be lumpy, cross-chop, and just plain ugly. By Saturday, the energy drops right off, and we're just dealin' with the leftovers of a dyin' swell.
And that's about it, folks. From Saturday the 8th all the way through until the middle of the next week, there is nothin' worth paddlin' out for. We're lookin' at a solid week of small, weak, and messy waves. The swell drops to 6ft and under, the periods get short and crumbly, and the wind just won't give us a break. It's flat, it's bumpy, and it's just plain sad. If you're a kite surfer, this stretch from the 8th to the 11th might be more up your alley, with those fresh cross-shore breezes and a bit of chop to play in.
There's a tiny glimmer of hope on Wednesday the 12th morning, but it's not worth gettin' excited about. A clean 3ft wave with a glassy wind, but it's got no energy behind it. It's surfable, but very ordinary.
The following week, things just stay flat and sleepy. We see a few ankle to knee-high pulses, but nothin' with any power or form. The winds are mostly light or glassy, which is a tease – it looks clean, but there’s just no swell. The river mouth is a rare break as it is, and for most of this period, it's not even gonna be breaking.
So, here's the bottom line. Your one and only shot is Wednesday morning, the 5th of August. It's a big, powerful, expert-only wave, and the conditions should be clean. After that, the ocean goes to sleep for a while.
This is Rusty, signin' off. Keep an eye on the charts, things can change. But for now, it's lookin' like a long, flat spell.
Short Range ForecastLight rain (total 3mm), mostly falling on Fri afternoon. Warm (max 33°C on Thu morning, min 26°C on Wed night). Winds increasing (calm on Wed morning, fresh winds from the E by Fri morning). | Days 4-6 Weather SummaryModerate rain (total 16mm), heaviest on Sat afternoon. Warm (max 30°C on Sun morning, min 26°C on Mon night). Mainly fresh winds. | ||||||||||||||||||||
Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | |||||||||||||||
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 16 | ESE 16 | SE 15 | SE 14 | SE 15 | SSE 16 | SSE 14 | SSE 14 | S 14 | ESE 10 | ESE 9 | ESE 9 | ESE 8 | ESE 8 | S 14 | ESE 13 | ESE 7 | ESE 7 | ESE 7 | ESE 7 | E 11 |
Wave Graph | |||||||||||||||||||||
11232 | 12248 | 9900 | 10442 | 12563 | 15580 | 9651 | 9434 | 4207 | 1609 | 1236 | 950 | 789 | 536 | 4163 | 2265 | 632 | 239 | 340 | 192 | 566 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-on | cross-off | cross | cross | cross-off | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-off |
High Tide | 10:00AM1.47m | 9:57PM1.67m | 11:18AM1.36m | 10:41PM1.60m | 1:19PM1.32m | 11:46PM1.54m | 3:23PM1.42m | 1:20AM1.53m | 4:31PM1.57m | 2:49AM1.60m | 5:17PM1.70m | 3:58AM1.71m | 5:54PM1.79m | ||||||||
Low Tide | 3:42PM0.77m | 4:49AM0.54m | 4:29PM0.96m | 6:05AM0.52m | 5:47PM1.13m | 7:38AM0.45m | 8:01PM1.21m | 9:02AM0.31m | 9:40PM1.16m | 10:06AM0.16m | 10:38PM1.05m | 10:58AM0.04m | 11:23PM0.92m | ||||||||
5:18 | — | — | 5:20 | — | — | 5:20 | — | — | 5:20 | — | — | 5:22 | — | — | 5:22 | — | — | 5:22 | — | — | |
— | 7:01 | — | — | 7:00 | — | — | 7:00 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:55 | — | |
mm | — | — | — | — | — | — | — | 2 | 1 | 2 | 5 | 4 | 1 | 3 | 1 | — | — | — | — | — | — |
Temp °C | 31 | 32 | 27 | 33 | 33 | 28 | 30 | 30 | 27 | 29 | 28 | 27 | 30 | 28 | 27 | 29 | 29 | 27 | 29 | 29 | 27 |
Feels °C | 33 | 34 | 31 | 32 | 32 | 30 | 29 | 29 | 28 | 29 | 29 | 28 | 29 | 28 | 27 | 27 | 27 | 28 | 31 | 30 | 31 |
Swell 1 Height (m) Direction Period (s) | ESE 16 | ESE 16 | SE 15 | SE 14 | SE 15 | SSE 16 | SSE 14 | SSE 14 | S 14 | SSW 14 | SSW 14 | SSW 14 | SSW 15 | SSW 14 | S 14 | SSW 14 | SSW 14 | SSW 14 | SSW 13 | SSW 12 | SSW 12 |
11232 | 12248 | 9900 | 10442 | 12563 | 15580 | 9651 | 9434 | 4207 | 3891 | 4136 | 3949 | 4432 | 3240 | 4163 | 2680 | 2834 | 3323 | 2318 | 1715 | 1444 | |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | — | — | E 16 | E 15 | E 15 | E 15 | E 15 | — | — | E 13 | E 14 | SE 15 | SE 14 | E 12 | E 12 | E 11 | ESE 13 |
— | — | — | — | — | — | 20 | 18 | 17 | 17 | 17 | — | — | 513 | 637 | 8 | 8 | 229 | 172 | 163 | 17 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | SE 15 | SE 15 | — | — | ESE 14 | SE 13 | ESE 13 | ESE 13 |
— | — | — | — | — | — | — | — | — | — | — | — | — | 9 | 9 | — | — | 19 | 27 | 17 | 17 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | E 8 | — | ESE 10 | ESE 10 | ESE 9 | ESE 9 | ESE 8 | ESE 8 | ESE 14 | ESE 13 | ESE 7 | ESE 7 | ESE 7 | ESE 7 | E 11 |
— | — | — | — | — | — | 682 | — | 2260 | 1609 | 1236 | 950 | 789 | 536 | 2453 | 2265 | 632 | 239 | 340 | 192 | 566 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 566 | 0 | 77 | 531 | 57 | 515 | 531 | 425 | 559 | 515 | 515 | 515 | 515 | 1514 | 1514 | 1510 | 1044 | 337 | 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.











