Surf Forecasts:
Kugenuma Rivermouth surf forecast from 7 Sep 2026:
- Best quality surf: Monday 7 Sep, 6PM (local time) - 10ft (3.0m), 9s period, S swell with offshore winds.
- Most powerful swell: Monday 7 Sep, 3PM (local time) - 10ft (3.0m), 9s period, S swell with 1,597 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 6PM (local time) - 10ft (3.0m), 9s 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 Monday (Sep 07) at 6PM. The primary swell is predicted to be 3.0m and 9s period with a secondary swell of 2.1m and 9s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Kugenuma Rivermouth in the next 16 days are 3.0m 9s and forecast to arrive on Monday (Sep 07) at 3PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 4s period and expected on Wednesday (Sep 09) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Mon 7th Sep) | 10ft (3.0m) 9s |
| Best Surf | 6PM (Mon 7th Sep) | 10ft (3.0m) 9s |
| Most Powerful | 3PM (Mon 7th Sep) | 10ft (3.0m) 9s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright folks, Rusty here with a look at what’s coming up for Kugenuma Rivermouth. Let’s get into it.
Right off the bat, we’ve got a bit of a messy start on Monday the 7th. Heavy rain and a light cross-on wind are mixing with a solid 6ft S swell, but it’s not clean. The water’s sitting at a noticeably warm 83°F, which is a touch warmer than what you’d normally expect for this time of year. Honestly, Monday afternoon looks a bit more powerful, with the swell jumping to 10ft from the S, but that heavy cross-wind is going to make it a choppy, unruly beast. Best to sit this one out unless you’re after a challenge.
Now, Tuesday the 8th is where things get interesting. Tuesday morning is the stand-out session of this whole outlook. We’re looking at clean 4ft S swell, but the wind is glassy – dead calm. That’ll put you right into some clean, lined-up waves at the rivermouth. It’s not huge, but it’ll be fun on a log or a fish. By Tuesday afternoon the wind swings onshore from the SSW at 16 mph and the swell drops off, so that morning window is your golden hour.
Wednesday the 9th is a write-off with onshore winds and poor conditions, so don’t even bother.
From Thursday the 10th onward, the surf just fades away. We get a few small days with clean offshore winds, but the swell drops below 3ft. By Friday the 11th, we’re down to 2ft and barely any energy. There’s a persistent stretch of small, weak surf from the 13th all the way through to the end of the forecast on the 22nd. So yeah, after that Tuesday morning blast, it’s a long, flat dead spell with absolutely nothing worth paddling out for.
The only one worth setting the alarm for is Tuesday morning, the 8th. Kugenuma Rivermouth with glassy 4ft S swell. That’s your one real shot.
Rusty.
Short Range ForecastHeavy rain (total 86mm), heaviest during Mon morning. Warm (max 28°C on Tue morning, min 21°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 8mm), mostly falling on Thu morning. Warm (max 25°C on Sat afternoon, min 20°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | |||||||||||||||
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 | S 9 | S 9 | SSW 10 | SSE 9 | SSW 9 | S 9 | S 9 | S 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 7 | SSW 7 | S 7 | SSW 7 | SSW 7 | SE 8 | SSW 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 497 | 1597 | 471 | 276 | 129 | 475 | 313 | 395 | 220 | 109 | 84 | 45 | 41 | 29 | 28 | 17 | 8 | 9 | 5 | 17 | 24 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | glassy | glassy | on | on | on | cross-off | off | off | off | off | off | off | off | off | glassy | glassy | glassy | on | on |
High Tide | 4:24PM1.40m | 1:50AM1.27m | 4:34PM1.43m | 2:58AM1.36m | 4:45PM1.45m | 3:46AM1.44m | 4:57PM1.47m | 4:26AM1.51m | 5:10PM1.49m | 5:03AM1.54m | 5:25PM1.52m | 5:39AM1.55m | 5:43PM1.56m | ||||||||
Low Tide | 9:35PM1.10m | 9:17AM0.35m | 9:58PM0.98m | 9:55AM0.33m | 10:20PM0.85m | 10:27AM0.35m | 10:42PM0.73m | 10:54AM0.39m | 11:05PM0.60m | 11:18AM0.46m | 11:30PM0.48m | 11:40AM0.54m | 11:59PM0.38m | ||||||||
 | |  |  |  |  |  |  |  |  |  |  |  | |  | | |  | | | | |
 | 5:18 | — | — | 5:18 | — | — | 5:18 | — | — | 5:20 | — | — | 5:20 | — | — | 5:20 | — | — | 5:22 | — | — |
 | — | 6:01 | — | — | 6:00 | — | — | 5:59 | — | — | 5:57 | — | — | 5:55 | — | — | 5:54 | — | — | 5:52 | — |
mm | 47 | 12 | 5 | — | 4 | 2 | — | 2 | 14 | 6 | 1 | 1 | — | — | — | — | — | — | — | — | 1 |
Temp °C | 22 | 24 | 25 | 28 | 28 | 27 | 28 | 25 | 22 | 21 | 22 | 20 | 21 | 21 | 21 | 23 | 25 | 24 | 26 | 27 | 26 |
Feels °C | 25 | 28 | 29 | 32 | 29 | 30 | 30 | 25 | 21 | 21 | 21 | 19 | 22 | 22 | 21 | 25 | 29 | 28 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | S 9 | S 9 | S 9 | S 9 | SSE 9 | SSW 10 | S 9 | — | S 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 7 | SSW 7 | S 7 | SSW 7 | SSW 7 | SE 8 | SE 7 |
| kJ | 497 | 670 | 471 | 276 | 129 | 193 | 313 | — | 220 | 109 | 84 | 45 | 41 | 29 | 28 | 17 | 8 | 9 | 5 | 17 | 14 |
Swell 2 Height (m) Direction Period (s) | — | SSW 9 | SSW 9 | SSW 10 | SSW 10 | SSE 8 | E 12 | E 16 | SE 9 | E 11 | SE 9 | SE 9 | SE 9 | SE 10 | SE 9 | SE 10 | SE 10 | SE 9 | SSE 7 | SSW 7 | SSW 11 |
| kJ | — | 631 | 315 | 264 | 96 | 80 | 3 | 5 | 3 | 2 | 14 | 3 | 3 | 4 | 3 | 4 | 4 | 3 | 5 | 5 | 24 |
Swell 3 Height (m) Direction Period (s) | — | — | SSW 11 | ESE 10 | E 10 | ESE 10 | ESE 10 | — | SE 11 | — | E 15 | E 16 | SE 9 | S 8 | S 8 | E 14 | E 14 | SE 8 | SE 9 | S 13 | SE 9 |
| kJ | — | — | 24 | 10 | 2 | 10 | 10 | — | 5 | — | 17 | 5 | 3 | 1 | 1 | 4 | 4 | 2 | 3 | 3 | 3 |
Wind waves Height (m) Direction Period (s) | N 3 | S 9 | — | — | — | SSW 9 | — | S 9 | NNE 4 | NE 3 | NNE 2 | NNE 3 | NNE 3 | NNE 3 | — | — | — | — | — | — | — |
| kJ | 3 | 1597 | — | — | — | 475 | — | 395 | 7 | 2 | 1 | 1 | 1 | 1 | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 2 | 2 | 0 | 0 | 89 | 7 | 130 | 2 | 30 | 0 | 0 | 2 | 57 | 45 | 24 | 24 | 24 | 24 | 24 | 64 | 30 |
Best forecast wave conditions in Kanagawa | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
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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.
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