Surf Forecasts:
Kugenuma Rivermouth surf forecast from 31 Jul 2026:
- Best quality surf: Thursday 6 Aug, 6AM (local time) - 11ft (3.5m), 17s period, S swell with offshore winds.
- Most powerful swell: Thursday 6 Aug, 9AM (local time) - 10ft (3.0m), 17s period, S swell with 6,085 kJ wave energy.
- Next surfable swell (1★+): Sunday 2 Aug, 6AM (local time) - 1.5ft (0.4m), 15s period with SE 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 Sunday (Aug 02) at 6AM. The primary swell is predicted to be 0.4m and 15s period with a secondary swell of 0.3m and 6s. 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 17s and forecast to arrive on Thursday (Aug 06) at 9AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Monday (Aug 03) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Sun 2nd Aug) | 1.5ft (0.4m) 15s |
| Best Surf | 6AM (Thu 6th Aug) | 11ft (3.5m) 17s |
| Most Powerful | 9AM (Thu 6th Aug) | 10ft (3.0m) 17s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright, folks, Rusty here. Let's break it down. The first week of August is a tale of two halves. We got some proper junk to start, but if you're patient, there's a window of solid, clean swell headed our way. Get ready to wait it out.
First up, Kugenuma Rivermouth is a total write-off. Friday and Saturday are flat with onshore slop, not worth a second look. The water's sitting at a warm 81°, which is right where you'd expect it for this time of year.
The real action starts to build on Monday, August 3rd. We get a solid injection of energy. The Monday morning session shows a 3ft swell from the SE with a very long 16-second period, and that's backed by a consistent NE offshore wind. The wave energy is moderate (323), and the conditions are set to be clean. Come Monday afternoon, it picks up to 3ft from the same direction, the period holds at 17 seconds, and the energy jumps to a strong 603. This is looking very good.
Now, the standout. You want to be locked in for Tuesday, August 4th. The morning is the pick. We're looking at a 6ft swell from the SE, a 17-second period, and a strong NE offshore wind. The combined energy hits a powerful 1858. This is excellent surf, but with that size, it's one for the experienced crew. Tuesday afternoon, the swell bumps up to 7ft, but the wind swings cross-offshore, making it a bit more manageable.
Wednesday, August 5th keeps the energy going. The morning has a 10ft swell from the SSE with a 17-second period and a light cross-offshore wind. The energy is a massive 4826. This is big, powerful, and only for experts. The wind stays clean, but at this size, a beach break like Kugenuma can get a bit unruly with that long period.
The swell hangs around through Thursday the 6th, but the wind turns onshore, and by Friday the 7th, it's dropping and getting messy. The second week from the 10th onwards looks like a return to small, ordinary conditions, so don't sleep on that first window.
Best bet: Tuesday morning, August 4th. Big, clean, and powerful. It's your best shot.
Rusty.
Short Range ForecastMostly dry. Warm (max 32°C on Sun morning, min 24°C on Sun night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Wed night. Warm (max 30°C on Tue afternoon, min 24°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | Wednesday 5 | Thursday 6 | |||||||||||||||
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 6 | S 6 | SSW 6 | SSW 7 | SSW 6 | SE 17 | ESE 16 | SE 15 | SE 15 | SE 16 | SE 18 | SE 17 | SE 17 | SE 17 | SE 16 | SSE 16 | SSE 17 | SSE 16 | S 17 | S 17 | S 16 |
Wave Graph  | |||||||||||||||||||||
 kJ | 20 | 21 | 13 | 9 | 13 | 46 | 99 | 104 | 107 | 258 | 614 | 974 | 1449 | 1859 | 2537 | 3192 | 4178 | 4862 | 6085 | 5404 | 3794 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | on | glassy | glassy | on | cross | cross-off | cross-on | off | off | off | off | off | cross-off | off | off | cross-off | cross-off | cross-off | on | cross |
High Tide | 6:46PM1.47m | 6:02AM1.50m | 7:08PM1.49m | 6:46AM1.45m | 7:32PM1.50m | 7:33AM1.36m | 8:00PM1.50m | 8:27AM1.25m | 8:29PM1.48m | 9:35AM1.12m | 9:01PM1.45m | 11:35AM1.03m | 9:37PM1.40m | ||||||||
Low Tide | 12:07PM0.19m | 00:21AM0.76m | 12:35PM0.28m | 00:57AM0.67m | 1:03PM0.40m | 1:38AM0.60m | 1:31PM0.54m | 2:25AM0.56m | 1:56PM0.69m | 3:24AM0.54m | 2:16PM0.86m | 4:41AM0.53m | 2:02PM1.01m | ||||||||
 | |  |  | | | | |  | |  |  | | | | | |  |  | | | |
 | 4:48 | — | — | 4:50 | — | — | 4:50 | — | — | 4:50 | — | — | 4:52 | — | — | 4:52 | — | — | 4:52 | — | — |
 | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 1 | — | — |
Temp °C | 30 | 30 | 28 | 29 | 30 | 28 | 32 | 30 | 26 | 26 | 27 | 26 | 28 | 30 | 26 | 28 | 30 | 27 | 30 | 29 | 27 |
Feels °C | 33 | 32 | 31 | 32 | 32 | 32 | 35 | 32 | 25 | 26 | 28 | 26 | 28 | 30 | 26 | 29 | 32 | 30 | 34 | 32 | 31 |
Swell 1 Height (m) Direction Period (s) | S 6 | SE 10 | SSW 6 | SSW 7 | SE 15 | SE 17 | ESE 16 | SE 15 | SE 15 | SE 16 | SE 18 | SE 17 | SE 17 | SE 17 | SE 16 | SSE 16 | SSE 17 | SSE 16 | S 17 | S 17 | S 16 |
| kJ | 20 | 4 | 13 | 9 | 8 | 46 | 99 | 104 | 107 | 258 | 614 | 974 | 1449 | 1859 | 2537 | 3192 | 4178 | 4862 | 6085 | 5404 | 3794 |
Swell 2 Height (m) Direction Period (s) | SE 9 | S 8 | SE 10 | SE 10 | SE 18 | SSW 4 | SSW 5 | SE 9 | SE 9 | SE 22 | S 8 | E 14 | — | E 13 | — | — | — | — | ESE 10 | ESE 10 | E 10 |
| kJ | 3 | 1 | 4 | 4 | 12 | 3 | 6 | 3 | 3 | 75 | 1 | 4 | — | 3 | — | — | — | — | 33 | 34 | 52 |
Swell 3 Height (m) Direction Period (s) | SE 12 | S 11 | S 8 | SE 15 | SE 9 | SSW 6 | SE 9 | SE 7 | SW 5 | S 8 | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 6 | 3 | 1 | 9 | 3 | 3 | 3 | 2 | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | S 6 | — | — | SSW 6 | — | — | S 5 | ENE 3 | NE 3 | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 21 | — | — | 13 | — | — | 9 | 2 | 3 | — | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 24 | 26 | 61 | 63 | 84 | 0 | 0 | 26 | 0 | 0 | 0 | 0 | 0 | 18 | 0 | 2 | 13 | 2 | 8 | 57 | 19 |
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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