Surf Forecasts:
Monabe Rivermouth surf forecast from 27 Jul 2026:
- Best quality surf: Monday 3 Aug, 9PM (local time) - 7.5ft (2.3m), 16s period, ESE swell with glassy winds.
- Most powerful swell: Tuesday 4 Aug, 9AM (local time) - 8ft (2.5m), 18s period, ESE swell with 4,059 kJ wave energy.
- Next surfable swell (1★+): Sunday 2 Aug, 9PM (local time) - 3.5ft (1.0m), 14s period with ESE 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 Sunday (Aug 02) at 9PM. The primary swell is predicted to be 1.0m and 14s period with a secondary swell of 0.4m and 18s. Another secondary swell of 0.5m and 6s 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 18s and forecast to arrive on Tuesday (Aug 04) at 9AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 5s period and expected on Tuesday (Jul 28) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Sun 2nd Aug) | 3.5ft (1.0m) 14s |
| Best Surf | 9PM (Mon 3rd Aug) | 7.5ft (2.3m) 16s |
| Most Powerful | 9AM (Tue 4th Aug) | 8ft (2.5m) 18s |
Table - best surf conditions forecast for Monabe Rivermouth over the next 16 days.
The Lowdown
Alright, grab a coffee and settle in. Rusty here, and I’ve got the lowdown on the Monabe Rivermouth scene. Let’s be straight up front: the next week and a half is a bit of a dud, but there is one absolute monster lurking in the second week for the real crew.
Right now, and for the next several days, we are staring at a flat spell. Nothing happening from Tuesday the 28th of July all the way through to Sunday the 2nd of August. We're talking tiny, weak dribbles that won’t even push you over the reef. The combined swell energy is weak (values between 28 and 179), so don’t bother paddling out. The water, sitting at a very warm 85°F, is much warmer than normal for this time of year, which is a consolation for the tan, but not for the stoke. The wind is often glassy or light, which is cruel irony – clean conditions but nothing to ride.
We finally get a bit on the charts starting Monday the 3rd of August, but it’s a marginal deal. Morning shows a building trend with 5ft swell from the ESE, but the onshore wind and questionable tide make it a tough sell. The energy picks up slightly (1207), but you’d be fighting for a messy closeout. Not recommended for a paddle.
Now, hold onto your leash. Wednesday the 5th of August is the one day we are looking at. This is a major standout. The morning brings in a huge 20ft groundswell from the East with a very long period of 19 seconds. The combined energy is massive at 25190, which is a serious amount of power. The wind goes glassy, dead calm. This is exceptional surf, but it is expert territory only – 20ft is big, gnarly, and powerful. The Rivermouth itself is sometimes crowded, and with that size and a long period, it’s going to be tricky, refracting hard off the river walls. If you have the skills, this is the session.
After that peak, the swell drops fast. Thursday the 6th sees cleaner, smaller 4ft waves but the wind picks up. And by Friday the 7th of August through to the end of the window, the wind howls from the east at near gale force (31-34 mph) with stormy looking conditions, making it a write-off. There’s a last gasp on Monday the 10th with a glassy morning and a clean 4ft E swell, but it’s ordinary.
So, to wrap it up: a long flat start, one absolutely pumping day for the big-wave chargers on the 5th of August, then a stormy finish.
Rusty.
Short Range ForecastMostly dry. Warm (max 32°C on Thu morning, min 26°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Sun afternoon. Warm (max 31°C on Fri morning, min 26°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 28 | Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | |||||||||||||||
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 10 | ESE 10 | SW 5 | SE 10 | ESE 10 | ESE 10 | ESE 10 | ESE 9 | ESE 9 | SE 9 | SE 9 | SE 9 | SE 10 | SE 10 | ESE 15 | ESE 14 | ESE 15 | ESE 15 | ESE 16 | ESE 16 | ESE 17 |
Wave Graph  | |||||||||||||||||||||
 kJ | 51 | 67 | 68 | 48 | 38 | 38 | 36 | 35 | 35 | 24 | 22 | 22 | 27 | 28 | 42 | 156 | 318 | 580 | 1121 | 1697 | 3090 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | off | cross | glassy | off | glassy | cross-on | off | glassy | on | glassy | glassy | on | glassy | glassy | on | cross-off | on | on | cross-off |
High Tide | 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 | 7:40AM1.75m | 8:28PM1.77m | 8:20AM1.68m | 8:54PM1.75m | ||||||||
Low Tide | 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 | 2:03PM0.30m | 2:26AM0.61m | 2:33PM0.43m | ||||||||
 | |  |  | | | | |  | | | | | | | |  | | | |  | |
 | 5:13 | — | — | 5:13 | — | — | 5:15 | — | — | 5:15 | — | — | 5:16 | — | — | 5:16 | — | — | 5:16 | — | — |
 | — | 7:07 | — | — | 7:07 | — | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | 1 | 4 | 1 |
Temp °C | 31 | 31 | 30 | 31 | 31 | 29 | 32 | 32 | 29 | 31 | 31 | 28 | 31 | 31 | 28 | 30 | 30 | 28 | 29 | 29 | 27 |
Feels °C | 35 | 35 | 34 | 36 | 35 | 33 | 33 | 35 | 32 | 33 | 34 | 32 | 34 | 34 | 33 | 34 | 33 | 34 | 33 | 33 | 32 |
Swell 1 Height (m) Direction Period (s) | S 8 | ESE 10 | SSW 5 | SW 5 | ESE 10 | SSW 5 | SSW 7 | ESE 9 | SW 5 | SE 9 | SE 9 | SE 9 | SE 10 | SE 10 | SE 11 | ESE 14 | ESE 15 | ESE 15 | ESE 16 | ESE 16 | ESE 17 |
| kJ | 51 | 67 | 61 | 23 | 38 | 17 | 21 | 35 | 15 | 23 | 22 | 22 | 27 | 28 | 30 | 156 | 318 | 580 | 1121 | 1697 | 3090 |
Swell 2 Height (m) Direction Period (s) | SE 10 | S 8 | SE 10 | SE 10 | SSW 8 | ESE 10 | ESE 10 | SW 6 | ESE 9 | SW 4 | SW 6 | SE 11 | SSW 4 | ESE 16 | ESE 15 | ESE 8 | SE 9 | SE 10 | SE 10 | S 8 | S 8 |
| kJ | 50 | 34 | 48 | 48 | 19 | 38 | 36 | 9 | 35 | 3 | 6 | 20 | 2 | 25 | 42 | 14 | 14 | 15 | 15 | 5 | 4 |
Swell 3 Height (m) Direction Period (s) | SE 13 | SE 13 | SSW 8 | SSW 8 | SE 13 | SSW 8 | SE 14 | SSW 7 | S 7 | SE 12 | ESE 13 | SSW 5 | S 7 | SSW 4 | E 11 | SSE 9 | ESE 20 | S 8 | S 8 | S 8 | SE 12 |
| kJ | 28 | 28 | 22 | 21 | 26 | 12 | 8 | 11 | 4 | 24 | 16 | 2 | 1 | 1 | 9 | 9 | 38 | 5 | 5 | 5 | 6 |
Wind waves Height (m) Direction Period (s) | SW 4 | SW 4 | SW 5 | WNW 3 | SW 5 | NW 3 | — | SW 5 | — | — | — | — | — | ENE 3 | — | — | E 5 | E 6 | E 6 | ESE 6 | — |
| kJ | 3 | 12 | 68 | 4 | 23 | 1 | — | 10 | — | — | — | — | — | 1 | — | — | 5 | 22 | 66 | 69 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 42 | 9 | 42 | 9 | 9 | 9 | 306 | 20 | 20 | 53 | 631 | 2400 | 528 | 9 | 9 | 50 | 0 | 20 | 75 | 0 |
Best forecast wave conditions in Shikoku | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Monabe Rivermouth surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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.
Nearest