Surf Forecasts:
Kugenuma Rivermouth surf forecast from 3 Sep 2026:
- Best quality surf: Thursday 10 Sep, 12PM (local time) - 4.5ft (1.4m), 9s period, S swell with cross-offshore winds.
- Most powerful swell: Tuesday 8 Sep, 3AM (local time) - 10ft (3.0m), 10s period, S swell with 1,738 kJ wave energy.
- Next surfable swell (1★+): Friday 4 Sep, 12AM (local time) - 2ft (0.6m), 11s period with S swell.
Best Forecast Surf Conditions for Kugenuma Rivermouth this week:
The surf forecast for Kugenuma Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Sep 04) at 12AM. The primary swell is predicted to be 0.6m and 11s period. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Kugenuma Rivermouth in the next 16 days are 3.0m 10s and forecast to arrive on Tuesday (Sep 08) at 3AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 4s period and expected on Monday (Sep 07) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Fri 4th Sep) | 2ft (0.6m) 11s |
| Best Surf | 12PM (Thu 10th Sep) | 4.5ft (1.4m) 9s |
| Most Powerful | 3AM (Tue 8th Sep) | 10ft (3.0m) 10s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what Kugenuma Rivermouth (Japan) has got cookin’ for us over the next couple of weeks.
Right off the bat, I gotta be straight with you – this is a tough stretch. The next several days are pretty much a write-off. Thursday and Friday the 3rd and 4th offer tiny, weak waves, but the wind is all wrong on Thursday and the quality is just ordinary on Friday. We’ve got a real gap here from Saturday the 5th all the way through Monday the 7th where the swell drops into the dirt – we’re talking 0.7ft to 2ft, and while the wind is offshore, there’s just no energy to work with (combined energy around 16 to 37). It’s a full-on lull.
The first real event worth paddling out for looks like it’s shaping up for Tuesday the 8th of September. A solid pulse of southerly swell hits, with waves around 8ft in the morning. The combined energy jumps massively to 1145, so there’s a lot of power in the water. But here’s the catch – that swell is coming in with a strong onshore wind (SSW at 12-19 mph), so the surface is going to be chopped up. This is more of a beast for experts only. That size over 8ft and bumpy conditions means this isn’t a beginner-friendly day.
Now, if you’re patient and hold out, there is a true standout, and it’s worth waiting for. Thursday the 17th of September is your moment. Thursday morning brings a clean, glassy 4ft SSW groundswell with a period of 10 seconds. The wind is virtually dead calm, glassy as a lake. Combined energy is a solid 334, so there’s good push. This is the kind of morning where the river mouth will be offering some clean, lined-up walls. The water temp is around 81°, which is about normal for this time of year, so you won’t need a thick suit.
Before that, Wednesday the 16th has a little something for the morning with 3ft to 4ft and clean conditions, but it’s not the standout. And Friday the 18th morning is glassy but only 3ft, which is just ordinary. Honesty, Thursday the 17th morning is your best bet in this whole window, but remember crowds are “often” here, especially when it cleans up.
So, word to the wise: the first week is a dud, the middle brings some size with messy wind, and the real score is that glassy morning on the 17th. Keep an eye on it.
Stay stoked,
Rusty
Short Range ForecastHeavy rain (total 44mm), heaviest during Sat morning. Warm (max 30°C on Thu afternoon, min 21°C on Sat morning). Winds increasing (calm on Thu night, strong winds from the N by Sat night). | Days 4-6 Weather SummaryHeavy rain (total 202mm), heaviest during Mon night. Warm (max 28°C on Tue morning, min 20°C on Sun night). Mainly strong winds. | ||||||||||||||||||||
Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | |||||||||||||||
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) | S 9 | SSW 4 | S 11 | S 10 | S 10 | SSW 9 | SSW 9 | SSW 9 | SSW 8 | SSW 9 | SE 7 | SE 7 | SE 7 | SE 7 | S 9 | S 10 | S 10 | S 10 | S 9 | S 9 | S 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 39 | 19 | 91 | 73 | 49 | 49 | 35 | 26 | 14 | 8 | 10 | 13 | 13 | 27 | 994 | 1131 | 776 | 500 | 904 | 551 | 408 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | glassy | off | off | cross-off | off | off | off | off | off | off | cross-off | cross-off | on | on | on | on | on | on | on |
High Tide | 9:15AM1.18m | 7:59PM1.49m | 11:18AM1.09m | 8:28PM1.42m | 9:04PM1.32m | 4:27PM1.34m | 11:39PM1.24m | 4:24PM1.40m | 1:50AM1.27m | 4:34PM1.43m | 2:58AM1.36m | 4:45PM1.45m | |||||||||
Low Tide | 1:27PM0.97m | 3:41AM0.47m | 12:52PM1.08m | 5:26AM0.51m | 7:15AM0.47m | 9:04PM1.21m | 8:27AM0.40m | 9:35PM1.10m | 9:17AM0.35m | 9:58PM0.98m | 9:55AM0.33m | 10:20PM0.85m | |||||||||
 |  |  | | |  |  | |  | | | | | |  |  | |  |  | | | |
 | 5:15 | — | — | 5:15 | — | — | 5:16 | — | — | 5:16 | — | — | 5:18 | — | — | 5:18 | — | — | 5:18 | — | — |
 | — | 6:07 | — | — | 6:06 | — | — | 6:04 | — | — | 6:02 | — | — | 6:01 | — | — | 6:00 | — | — | 5:59 | — |
mm | — | 2 | 1 | 1 | 5 | 17 | 18 | — | — | 1 | 5 | 17 | 39 | 20 | 109 | 1 | 1 | 9 | — | 3 | 6 |
Temp °C | 29 | 30 | 24 | 25 | 24 | 23 | 21 | 24 | 23 | 22 | 21 | 20 | 21 | 24 | 26 | 28 | 28 | 27 | 28 | 28 | 27 |
Feels °C | 30 | 32 | 24 | 28 | 27 | 25 | 19 | 22 | 20 | 16 | 16 | 14 | 17 | 28 | 25 | 28 | 28 | 30 | 28 | 27 | 29 |
Swell 1 Height (m) Direction Period (s) | S 9 | SE 10 | S 11 | S 10 | S 10 | SSW 9 | SSW 9 | SSW 9 | SSW 8 | SSE 8 | SE 7 | SE 7 | SE 7 | SE 7 | E 9 | S 10 | S 10 | S 10 | S 9 | E 16 | S 9 |
| kJ | 39 | 4 | 91 | 73 | 49 | 49 | 35 | 26 | 14 | 7 | 9 | 13 | 13 | 27 | 13 | 1131 | 776 | 500 | 397 | 5 | 408 |
Swell 2 Height (m) Direction Period (s) | SE 10 | S 13 | NNE 3 | SE 6 | SE 6 | SSE 6 | SE 6 | SE 7 | SSE 8 | SSW 9 | ESE 10 | ESE 11 | SSW 9 | SSW 9 | — | E 9 | E 9 | SSW 10 | SSW 9 | E 16 | SSW 9 |
| kJ | 4 | 3 | 1 | 9 | 11 | 4 | 2 | 7 | 7 | 8 | 10 | 11 | 7 | 8 | — | 14 | 7 | 151 | 121 | 5 | 113 |
Swell 3 Height (m) Direction Period (s) | E 10 | E 10 | SE 10 | SE 9 | SE 9 | SE 9 | SE 9 | SE 8 | E 7 | E 8 | SW 9 | S 9 | E 9 | S 11 | — | — | — | E 8 | E 17 | — | E 16 |
| kJ | 2 | 2 | 4 | 3 | 3 | 3 | 3 | 3 | 1 | 1 | 3 | 2 | 2 | 2 | — | — | — | 1 | 6 | — | 5 |
Wind waves Height (m) Direction Period (s) | — | SSW 4 | — | — | — | — | NNE 3 | NE 3 | NE 3 | NNE 4 | NNE 4 | NNE 4 | N 4 | N 3 | S 9 | — | — | — | S 9 | S 9 | — |
| kJ | — | 19 | — | — | — | — | 3 | 5 | 12 | 25 | 26 | 30 | 28 | 5 | 994 | — | — | — | 904 | 551 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 84 | 89 | 0 | 0 | 0 | 2 | 45 | 545 | 503 | 222 | 463 | 545 | 57 | 26 | 222 | 19 | 89 | 545 | 484 | 484 | 19 |
Best forecast wave conditions in Kanagawa | |||||||||||||||||||||
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 Kugenuma 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 Kugenuma Rivermouth Surf forecast
The above surf forecast table for Kugenuma Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Kugenuma Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Kugenuma 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 (Kugenuma 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 Kugenuma 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.
Nearest