Surf Forecasts:
Kugenuma Rivermouth surf forecast from 27 Aug 2026:
- Best quality surf: Friday 28 Aug, 6PM (local time) - 2.5ft (0.7m), 8s period, SSW swell with glassy winds.
- Most powerful swell: Wednesday 2 Sep, 3PM (local time) - 3.5ft (1.1m), 11s period, S swell with 279 kJ wave energy.
- Next surfable swell (1★+): Friday 28 Aug, 6PM (local time) - 2.5ft (0.7m), 8s period with SSW 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 (Aug 28) at 6PM. The primary swell is predicted to be 0.7m and 8s period with a secondary swell of 0.2m and 10s. Another secondary swell of 0.1m and 14s is also forecast. 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 1.1m 11s and forecast to arrive on Wednesday (Sep 02) at 3PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Saturday (Aug 29) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Fri 28th Aug) | 2.5ft (0.7m) 8s |
| Best Surf | 6PM (Fri 28th Aug) | 2.5ft (0.7m) 8s |
| Most Powerful | 3PM (Wed 2nd Sep) | 3.5ft (1.1m) 11s |
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's on the cards for Kugenuma Rivermouth over the next couple of weeks.
Straight up, it's a tough start. The first week and a bit is pretty grim, with a whole run of days delivering poor surf conditions. We’re looking at a dry spell from now right through until the morning of Friday the 4th of September where there's just nothing worth paddling out for. Onshore winds, messy chop, and tiny swell with weak combined energy – not our kind of party.
But hold on, there's a glimmer. Friday morning the 4th of September finally shows some life with surfable waves, but they're ordinary. The wind will be offshore from the NE at 12 mph though, so it'll be clean. The swell is a modest 2 ft from the SSW, with a period of 10 seconds, and the combined energy is moderate at 121. It's not a standout, but it's a start after a long wait.
The real standout, the one you want to circle in your calendar, is the morning of Friday the 11th of September. This is the best we’re going to see. The forecast shows a glassy offshore wind from the E at just 3 mph, which is an absolute treat. Expect clean, smooth conditions. The swell picks up to 4 ft from the S with a 9-second period, producing moderate combined energy (250). This is the session to aim for. It's a river mouth break so it can handle that period just fine. It is also a fairly consistent spot, but crowds are likely here at Kugenuma Rivermouth, so get there early.
Water temp at the start of the period is 83°, which is a touch warmer than normal for this time of year. Keep that in mind if you're not used to warm water.
After that glassy Friday, things drop off again quickly. Saturday the 12th of September morning offers a small, clean option with an ENE cross-offshore wind, but the swell is tiny at 2 ft from the S and the combined energy is weak (81). It's an ordinary session, nothing more.
So, to sum it up: suffer through the drought, and make your move on the morning of Friday the 11th of September. That’s the one.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Fri morning. Warm (max 29°C on Fri afternoon, min 22°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Tue night. Warm (max 28°C on Mon morning, min 26°C on Mon morning). Mainly fresh winds. | ||||||||||||||||||||
Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 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) | SW 6 | SSW 7 | SSW 7 | SSW 7 | SSW 8 | SSW 8 | SSE 10 | SSE 10 | SSW 8 | S 12 | SSW 10 | S 11 | SSW 10 | SSW 10 | SSW 10 | S 10 | S 11 | SSW 10 | SSW 11 | SSW 11 | SSW 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 122 | 64 | 42 | 18 | 12 | 12 | 10 | 10 | 11 | 10 | 21 | 58 | 77 | 104 | 139 | 177 | 279 | 115 | 206 | 117 | 121 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | off | cross-off | cross-off | off | off | cross-off | glassy | on | on | on | cross-on | cross-on | cross-on | on | cross-on | on | on | on | cross-on |
High Tide | 5:42PM1.49m | 5:22AM1.55m | 5:58PM1.52m | 6:00AM1.54m | 6:18PM1.55m | 6:40AM1.50m | 6:40PM1.58m | 7:22AM1.41m | 7:05PM1.57m | 8:12AM1.30m | 7:32PM1.55m | 9:15AM1.18m | 7:59PM1.49m | ||||||||
Low Tide | 11:19AM0.31m | 11:29PM0.65m | 11:43AM0.38m | 11:57PM0.54m | 12:07PM0.47m | 00:28AM0.45m | 12:30PM0.58m | 1:04AM0.40m | 12:53PM0.70m | 1:45AM0.39m | 1:14PM0.83m | 2:34AM0.42m | 1:27PM0.97m | ||||||||
 |  |  |  | | | | |  |  | |  | | |  | | | | | | | |
 | 5:09 | — | — | 5:11 | — | — | 5:11 | — | — | 5:11 | — | — | 5:13 | — | — | 5:13 | — | — | 5:15 | — | — |
 | — | 6:15 | — | — | 6:14 | — | — | 6:13 | — | — | 6:10 | — | — | 6:09 | — | — | 6:08 | — | — | 6:07 | — |
mm | 1 | — | — | — | 2 | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Temp °C | 27 | 29 | 28 | 26 | 24 | 23 | 24 | 24 | 24 | 28 | 28 | 27 | 28 | 28 | 27 | 28 | 28 | 28 | 29 | 30 | 28 |
Feels °C | 29 | 31 | 31 | 26 | 26 | 22 | 25 | 26 | 27 | 30 | 28 | 29 | 31 | 30 | 30 | 29 | 28 | 29 | 29 | 30 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 6 | SSE 9 | SSW 7 | SSW 7 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SSW 7 | SSW 10 | S 11 | SSW 10 | SSW 10 | SSW 10 | S 10 | S 11 | SSW 10 | SSW 11 | SSW 11 | SSW 11 |
| kJ | 33 | 8 | 42 | 18 | 11 | 12 | 6 | 6 | 11 | 5 | 21 | 58 | 77 | 104 | 139 | 177 | 279 | 115 | 206 | 117 | 121 |
Swell 2 Height (m) Direction Period (s) | S 9 | SE 15 | SSE 10 | SSE 11 | SSE 11 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 9 | SSE 10 | SE 10 | SE 10 | SE 10 | SE 10 | SSW 12 | SE 7 | SE 7 | SE 7 |
| kJ | 14 | 8 | 9 | 11 | 12 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 4 | 4 | 4 | 4 | 60 | 42 | 105 | 7 |
Swell 3 Height (m) Direction Period (s) | SSE 9 | SW 9 | SSE 10 | — | SSW 8 | — | ESE 6 | ESE 5 | — | S 12 | E 13 | SSW 13 | E 11 | E 11 | E 11 | E 10 | E 10 | E 10 | E 10 | SE 10 | SE 8 |
| kJ | 8 | 3 | 18 | — | 11 | — | 3 | 3 | — | 10 | 3 | 18 | 2 | 2 | 2 | 2 | 2 | 8 | 7 | 4 | 9 |
Wind waves Height (m) Direction Period (s) | SW 6 | SSW 7 | — | NNE 2 | ENE 2 | ENE 3 | — | — | SW 3 | SSW 3 | S 4 | SSW 3 | — | — | — | SE 6 | SE 6 | SSE 6 | — | SSE 4 | S 4 |
| kJ | 122 | 64 | — | 1 | 1 | 1 | — | — | 1 | 1 | 12 | 4 | — | — | — | 31 | 75 | 48 | — | 28 | 16 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 19 | 7 | 0 | 57 | 105 | 63 | 61 | 24 | 63 | 84 | 89 | 7 | 26 | 64 | 19 | 26 | 85 | 19 | 88 | 512 | 7 |
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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