
Surf Forecasts:
Monabe Rivermouth surf forecast from 23 Jul 2026:
- Most powerful swell: Saturday 25 Jul, 3AM (local time) - 1.5ft (0.4m), 16s period, SE swell with 94 kJ wave energy.
Best Forecast Surf Conditions for Monabe Rivermouth this week:
The most powerful waves expected at Monabe Rivermouth in the next 16 days are 0.4m 16s and forecast to arrive on Saturday (Jul 25) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 8s period and expected on Tuesday (Jul 28) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 3AM (Sat 25th Jul) | 1.5ft (0.4m) 16s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s break down what’s happening for the next couple of weeks.
Honestly, the first week and a half is a total washout. We’re looking at a long stretch of nothing but tiny, weak waves with poor conditions. The swell energy is basically non-existent, so don’t even bother checking the cams until we get into the second week of August.
The only real hope on this entire 16-day forecast is for Monabe Rivermouth. This spot is a river mouth, so it’s very sheltered and it rarely breaks, but when it does, it’s a special day. The wait is long, but it might just be worth it.
The action *finally* starts to fire up on Tuesday, August 4th. The morning is looking absolutely pristine. We’ve got a glassy, calm start with a solid 7ft swell rolling in from the ESE. The period is a very long 16 seconds, which is proper groundswell energy. The combined energy jumps right up to a strong 2123, so there’s real power behind it. This is a setup for clean, lined-up waves, but because it’s a river mouth, that long-period swell should wrap in nicely. The water temperature is 84°, which is a touch warmer than normal for this time of year.
The swell keeps building through the week. Wednesday, August 5th morning is another glassy winner with 8ft from the ESE, and the energy is even stronger at 2741. The trend continues into Thursday, August 6th morning with 8ft and a huge energy reading of 3752, again with glassy offshore winds. This is the sweet spot – big, powerful, and clean. Anything over 8ft gets into expert territory, so keep that in mind.
By Friday, August 7th, things get a bit wild. The swell is 13ft to 15ft with a massive 18-second period. The energy is off the charts. The wind is strong offshore from the NNW, which will be clean, but that north wind might make paddling out a battle. This is for the big-wave crew and experts only.
Then Saturday, August 8th looks like it gets completely blown out and way too big to surf with the onshore wind. The setup would be more interesting for kite surfing than paddle surfing.
So, the standout window is the mornings of the 4th, 5th, and 6th of August. The glassy conditions and building ESE groundswell at Monabe Rivermouth are the only real highlights here. Just remember, this spot is inconsistent and rarely breaks, so when it does, it’s a special one. Crowds are possible, so get there early.
Rusty.
Short Range ForecastSome drizzle, heaviest during Sun afternoon. Warm (max 32°C on Sat morning, min 26°C on Sun night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 32°C on Wed morning, min 26°C on Tue night). Wind will be generally light. | ||||||||||||||||||||
Friday 24 | Saturday 25 | Sunday 26 | Monday 27 | Tuesday 28 | Wednesday 29 | Thursday 30 | |||||||||||||||
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 18 | SE 18 | SE 16 | SE 16 | SE 16 | SE 16 | SE 15 | SE 15 | SE 14 | SE 14 | S 9 | S 8 | SE 10 | ESE 10 | SE 10 | SE 10 | ESE 10 | ESE 10 | ESE 10 | ESE 9 | ESE 10 |
Wave Graph | |||||||||||||||||||||
49 | 49 | 42 | 91 | 90 | 87 | 78 | 76 | 74 | 72 | 76 | 71 | 50 | 67 | 48 | 48 | 38 | 38 | 36 | 35 | 37 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | off | glassy | on | glassy | glassy | on | off | glassy | on | off | on | on | off | glassy | cross-on | glassy | glassy | on | off |
High Tide | 4:03PM1.34m | 1:37AM1.44m | 4:53PM1.44m | 2:50AM1.47m | 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 | ||||||||
Low Tide | 8:22PM1.21m | 9:22AM0.50m | 9:48PM1.18m | 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 | ||||||||
5:11 | — | — | 5:11 | — | — | 5:11 | — | — | 5:13 | — | — | 5:13 | — | — | 5:13 | — | — | 5:15 | — | — | |
— | 7:10 | — | — | 7:09 | — | — | 7:09 | — | — | 7:08 | — | — | 7:07 | — | — | 7:07 | — | — | 7:07 | — | |
mm | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 31 | 31 | 28 | 32 | 31 | 28 | 31 | 30 | 28 | 30 | 30 | 28 | 30 | 30 | 27 | 32 | 32 | 29 | 31 | 31 | 28 |
Feels °C | 35 | 35 | 33 | 36 | 35 | 33 | 35 | 34 | 33 | 34 | 34 | 34 | 34 | 34 | 32 | 34 | 35 | 34 | 35 | 35 | 34 |
Swell 1 Height (m) Direction Period (s) | SE 10 | SE 18 | SE 11 | SE 11 | SE 10 | SE 10 | SE 10 | S 9 | S 8 | S 8 | S 9 | S 8 | SSW 8 | S 8 | SSW 8 | SE 10 | ESE 10 | ESE 10 | ESE 10 | ESE 9 | ESE 10 |
14 | 49 | 42 | 41 | 37 | 49 | 50 | 56 | 49 | 50 | 76 | 71 | 57 | 50 | 38 | 48 | 38 | 38 | 36 | 35 | 37 | |
Swell 2 Height (m) Direction Period (s) | SE 18 | SSW 4 | SE 16 | SE 16 | SE 16 | SE 16 | S 9 | SE 11 | SE 11 | SE 10 | ESE 10 | SE 10 | SE 10 | ESE 10 | SE 10 | SSW 8 | SSW 8 | SSW 5 | SSW 5 | SSW 7 | SSW 7 |
49 | 3 | 42 | 91 | 90 | 87 | 41 | 55 | 57 | 37 | 68 | 51 | 50 | 67 | 48 | 22 | 21 | 10 | 5 | 11 | 17 | |
Swell 3 Height (m) Direction Period (s) | SSW 4 | SE 9 | E 9 | E 9 | S 8 | SSW 8 | SE 15 | SE 15 | SE 14 | SE 14 | SE 14 | SE 14 | SE 13 | SE 13 | SE 13 | SSW 4 | SSW 5 | SSW 8 | SSW 8 | SSW 4 | SE 12 |
3 | 14 | 15 | 6 | 10 | 11 | 78 | 76 | 74 | 72 | 71 | 29 | 28 | 28 | 27 | 6 | 4 | 11 | 11 | 4 | 6 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | WSW 4 | — | — | — | — | — | SW 3 | — | — | — | — | — | — | — | — | — |
— | — | — | — | — | 2 | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 42 | 9 | 9 | 42 | 9 | 9 | 20 | 9 | 9 | 53 | 9 | 9 | 53 | 9 | 9 | 57 | 9 | 20 | 631 | 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.










