
Surf Forecasts:
Monabe Rivermouth surf forecast from 25 Jul 2026:
- Best quality surf: Monday 27 Jul, 6PM (local time) - 2.5ft (0.7m), 9s period, S swell with glassy winds.
- Most powerful swell: Sunday 26 Jul, 9AM (local time) - 1.5ft (0.4m), 15s period, SE swell with 78 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 6PM (local time) - 2.5ft (0.7m), 9s 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 (Jul 27) at 6PM. The primary swell is predicted to be 0.7m and 9s period with a secondary swell of 0.6m and 10s. 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 0.4m 15s and forecast to arrive on Sunday (Jul 26) 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 0.8m 5s period and expected on Wednesday (Jul 29) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Mon 27th Jul) | 2.5ft (0.7m) 9s |
| Best Surf | 6PM (Mon 27th Jul) | 2.5ft (0.7m) 9s |
| Most Powerful | 9AM (Sun 26th Jul) | 1.5ft (0.4m) 15s |
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 the cards for this stretch of coast.
To be straight with you, the next week or so is pretty quiet. There’s a lot of clean, glassy mornings with tiny swell – we’re talking 1.0ft to 2ft – and the combined energy is weak, often under 100. It’s not doing much at all. The waves are there, but they’re barely a bump. You’d be scratching for a ride. This lull runs right through until the end of July and into the first few days of August.
The one big standout is a major pulse that arrives around the 4th of August and builds into a monster. The real gem is Monday morning, the 10th of August. That’s when things get wild. But before that, on the 8th of August, we’ve got some serious energy.
Let’s talk about the main event. The best of the best is Saturday morning, the 8th of August. Monabe Rivermouth is a river break, and it’s a rare one. It rarely breaks, so when it does, you pay attention. The swell is pumping from the ESE at 28ft, with a very long period of 19 seconds – that’s proper groundswell. The combined energy is a massive 50128, which is very strong. The wind is a moderate offshore from the N at 16 mph, keeping it clean. The water temp is 85°, which is a whopping 4° warmer than normal – much warmer than average for this time of year. This is a setup for experts only. That 28ft is way over the 8ft mark, so it’s too big for beginners. The long period and ESE direction will suit this river break well, but it’s going to be a wild, powerful beast. Crowds are sometimes a problem here, so with a rare, massive swell, expect company.
The morning of the 7th of August is also a cracker for the brave. Friday morning has a 16ft swell from the ESE at 18 seconds, with glassy conditions. The energy is 16165, still very strong. That’s another expert-only session.
By the 8th, Saturday afternoon, the wind swings to a cross-offshore from the NE at 22 mph, but the swell is up to 30ft, so it’s still huge and powerful.
Now, the 9th of August swings into the danger zone. The swell is 46ft on Sunday morning, with a cross-onshore near gale at 34 mph. That’s too big for this break, and the wind is going to make it a mess. The afternoon isn’t much better. This is more of a kite surfing show, if you ask me, not a paddle session.
The 10th of August, Monday morning, the swell is still a solid 21ft from the S at 12 seconds, but the wind is onshore from the S at 9 mph. It’s holding some size, but the quality drops off.
So, the long story short: the first week is a write-off. The action starts on the 4th of August and builds to a massive peak on the 8th. For the true standouts, lock in Saturday morning, the 8th of August, at Monabe Rivermouth for the biggest, cleanest, most powerful swell of the window. That’s the one you want to be on. The morning of the 7th is your second pick. Everything else before that is a flat spell or just too big and ragged.
Rusty.
Short Range ForecastSome drizzle, heaviest during Mon afternoon. Warm (max 32°C on Sun morning, min 27°C on Sun night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Thu night. Warm (max 31°C on Wed afternoon, min 26°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Sunday 26 | Monday 27 | Tuesday 28 | Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | |||||||||||||||
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) | SE 15 | SE 15 | SE 14 | SE 14 | S 9 | S 8 | SE 10 | ESE 10 | SE 10 | SE 10 | SE 10 | ESE 10 | ESE 10 | ESE 9 | ESE 9 | SE 13 | SE 9 | SE 9 | ESE 10 | SE 10 | SE 11 |
Wave Graph | |||||||||||||||||||||
78 | 76 | 74 | 72 | 74 | 71 | 51 | 67 | 48 | 48 | 48 | 38 | 36 | 35 | 35 | 25 | 24 | 22 | 41 | 39 | 42 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | off | glassy | on | off | glassy | on | off | glassy | on | off | glassy | on | glassy | glassy | on | glassy | glassy | on | off |
High Tide | 5:27PM1.53m | 3:48AM1.54m | 5:56PM1.60m | 4:35AM1.62m | 6:23PM1.66m | 5:15AM1.70m | 6:49PM1.71m | 5:52AM1.76m | 7:14PM1.74m | 6:28AM1.79m | 7:38PM1.76m | 7:03AM1.79m | 8:03PM1.77m | ||||||||
Low Tide | 10:13AM0.41m | 10:39PM1.11m | 10:54AM0.31m | 11:15PM1.04m | 11:31AM0.23m | 11:47PM0.96m | 12:04PM0.17m | 00:17AM0.88m | 12:35PM0.14m | 00:48AM0.81m | 1:05PM0.16m | 1:19AM0.73m | 1:34PM0.21m | 1:51AM0.67m | |||||||
5:11 | — | — | 5:13 | — | — | 5:13 | — | — | 5:13 | — | — | 5:15 | — | — | 5:15 | — | — | 5:16 | — | — | |
— | 7:09 | — | — | 7:08 | — | — | 7:07 | — | — | 7:07 | — | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | |
mm | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Temp °C | 32 | 31 | 28 | 30 | 31 | 28 | 31 | 31 | 28 | 29 | 31 | 29 | 31 | 31 | 28 | 31 | 31 | 28 | 31 | 31 | 27 |
Feels °C | 35 | 34 | 33 | 34 | 35 | 33 | 35 | 35 | 33 | 33 | 34 | 32 | 33 | 34 | 33 | 33 | 34 | 32 | 34 | 35 | 32 |
Swell 1 Height (m) Direction Period (s) | SE 10 | S 9 | S 8 | S 8 | S 9 | S 8 | S 8 | ESE 10 | SSW 5 | SSW 5 | SE 10 | SW 5 | ESE 10 | ESE 9 | ESE 9 | SE 9 | SE 9 | SW 4 | ESE 10 | SE 10 | SE 11 |
50 | 56 | 49 | 50 | 74 | 71 | 51 | 67 | 20 | 18 | 48 | 18 | 36 | 35 | 35 | 22 | 21 | 16 | 41 | 39 | 42 | |
Swell 2 Height (m) Direction Period (s) | S 9 | SE 11 | SE 11 | SE 10 | ESE 10 | SE 10 | SE 10 | S 8 | SE 10 | SE 10 | SSW 8 | ESE 10 | SSW 8 | SW 6 | SSW 7 | SSW 4 | SE 12 | SE 9 | SSW 4 | S 4 | SSW 4 |
41 | 55 | 57 | 37 | 68 | 51 | 50 | 34 | 48 | 48 | 12 | 38 | 11 | 8 | 5 | 3 | 24 | 22 | 3 | 3 | 4 | |
Swell 3 Height (m) Direction Period (s) | SE 15 | SE 15 | SE 14 | SE 14 | SE 14 | SE 14 | SE 13 | SSW 4 | SSW 8 | SSW 8 | SE 13 | SSW 8 | SW 4 | SSW 7 | SE 12 | SE 13 | S 7 | SE 11 | S 7 | SW 6 | ESE 9 |
78 | 76 | 74 | 72 | 71 | 29 | 28 | 4 | 22 | 21 | 26 | 11 | 5 | 11 | 6 | 25 | 4 | 20 | 1 | 6 | 8 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | SSW 4 | SW 3 | — | — | SW 5 | — | SSW 5 | SW 4 | — | — | SW 4 | — | SSW 4 | — | — | — | — |
— | — | — | — | 1 | 4 | — | — | 40 | — | 19 | 20 | — | — | 4 | — | 3 | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 53 | 9 | 9 | 50 | 9 | 9 | 42 | 9 | 9 | 9 | 9 | 9 | 42 | 20 | 9 | 42 | 9 | 432 | 516 | 20 |
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.










