
Surf Forecasts:
Kugenuma Rivermouth surf forecast from 21 Jul 2026:
- Best quality surf: Thursday 23 Jul, 3AM (local time) - 3ft (0.9m), 6s period, SW swell with cross-offshore winds.
- Most powerful swell: Monday 27 Jul, 6AM (local time) - 4ft (1.2m), 6s period, SSE swell with 87 kJ wave energy.
- Next surfable swell (1★+): Thursday 23 Jul, 3AM (local time) - 3ft (0.9m), 6s period with SW 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 Thursday (Jul 23) at 3AM. The primary swell is predicted to be 0.9m and 6s period with a secondary swell of 0.6m and 5s. Another secondary swell of 0.1m and 11s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Kugenuma Rivermouth in the next 16 days are 1.2m 6s and forecast to arrive on Monday (Jul 27) at 6AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.5m 3s period and expected on Monday (Jul 27) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Thu 23rd Jul) | 3ft (0.9m) 6s |
| Best Surf | 3AM (Thu 23rd Jul) | 3ft (0.9m) 6s |
| Most Powerful | 6AM (Mon 27th Jul) | 4ft (1.2m) 6s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here. Let's take a look at what's on the cards for the Kugenuma Rivermouth stretch.
First up, I gotta be straight with you – the next week or so is looking pretty grim. We’re talking a long stretch of flat, weak, and poor conditions. From Wednesday the 22nd right through to the end of July, the energy is just not there. The swell is tiny, often under 2 feet, with a combined energy reading that barely cracks double digits. Even when the wind goes glassy or offshore, there’s just nothing to work with. It’s a real bummer.
Now, Monday the 27th of July morning offers a little glimmer – a tiny 2 foot wrap from the SSE with glassy conditions and a combined energy of 60. It’s surfable, but only just. You’d be on a foamie, and you’d be scratching for anything. Not a standout by any stretch.
The real interest, and I mean the only thing that gets my blood pumping, is the first week of August. Things start to shake up a little on the 1st of August Saturday morning. We’ve got a 1.0 foot SSE swell with a long period of 13 seconds and a clean offshore wind. The combined energy is 73. Still small, but it’s a step in the right direction.
Then, Sunday the 2nd of August morning is where it starts to get interesting. A 2 foot south swell with a 13-second period, glassy conditions, and the combined energy jumps to 186. That’s moderate energy, and for a rivermouth setup, that long period groundswell can actually wrap in and give you some nice, lined-up waves. It’s still small, but the quality is there.
But the standout, the one you want to circle on the calendar, is Monday the 3rd of August. The morning brings a proper 6 foot south swell, with a 16-second period. That’s a very long period groundswell, and the combined energy is a thumping 1474 – strong wave energy. The wind is a light cross-onshore, which isn't perfect, but it's light. This is a big step up in size. The afternoon holds similar energy at 6 feet and 15 seconds, with a light onshore wind. This is a solid, powerful swell.
Tuesday the 4th of August is also a cracker. Morning brings a 5 foot south swell, with a moderate offshore wind from the NNE at 16 mph. The combined energy is 1393. The afternoon is even better for wind: a 5 foot SSW swell with a 19 mph offshore breeze from the NE. That’s fresh offshore and clean. The energy is still well over 1000. This is expert territory at that size, but for the experienced crew, those offshore winds on a solid, long-period groundswell will make the Kugenuma Rivermouth look its absolute best. The water temp is about average for this time of year, so no surprises there.
The wind does get a bit wild on the 5th and 6th of August, with strong to gale-force offshore winds, which will make it clean but a real battle to paddle out. The swell drops off quickly, so the 3rd and 4th of August are your prime windows.
So, to wrap it up: the first week is a write-off, but the 3rd and 4th of August are the real standouts. Get your board ready for that.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Thu night. Warm (max 32°C on Thu morning, min 26°C on Thu night). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 27mm), heaviest during Sun morning. Warm (max 27°C on Fri night, min 23°C on Sat night). Wind will be generally light. | ||||||||||||||||||
Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | Monday 27 | ||||||||||||||
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) | SSW 4 | SSW 4 | S 4 | SSW 5 | SSW 6 | SSW 6 | SSE 10 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SSE 15 | SE 15 | SE 11 | SE 5 | SSE 6 | SE 10 | SE 10 |
Wave Graph | |||||||||||||||||||
11 | 11 | 7 | 19 | 15 | 13 | 12 | 12 | 11 | 18 | 15 | 15 | 22 | 8 | 18 | 50 | 28 | 16 | 16 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | on | cross-on | cross-off | on | cross-off | cross-off | on | cross | off | off | off | off | cross | on | glassy | off | cross-off |
High Tide | 9:18PM1.42m | 10:39AM1.04m | 9:55PM1.40m | 10:41PM1.37m | 5:19PM1.20m | 11:42PM1.34m | 5:07PM1.30m | 00:58AM1.34m | 5:24PM1.37m | 2:08AM1.37m | 5:41PM1.41m | ||||||||
Low Tide | 4:33AM0.58m | 2:58PM0.89m | 6:01AM0.51m | 7:24AM0.41m | 6:26PM1.19m | 8:29AM0.31m | 8:49PM1.21m | 9:20AM0.21m | 9:49PM1.18m | 10:02AM0.15m | 10:26PM1.13m | ||||||||
— | 4:41 | — | — | 4:43 | — | — | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — | 4:46 | — | — | |
6:53 | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | |
mm | — | — | — | — | — | — | 3 | — | — | 3 | — | — | 2 | 7 | 5 | 8 | — | 2 | — |
Temp °C | 29 | 30 | 30 | 29 | 32 | 32 | 29 | 28 | 28 | 27 | 25 | 26 | 23 | 23 | 24 | 25 | 25 | 26 | 25 |
Feels °C | 33 | 34 | 34 | 31 | 36 | 35 | 34 | 31 | 31 | 31 | 25 | 26 | 23 | 26 | 28 | 27 | 29 | 28 | 28 |
Swell 1 Height (m) Direction Period (s) | SE 8 | SSW 4 | SE 8 | SE 11 | SSW 6 | SE 10 | S 5 | SSW 6 | SSE 9 | SE 11 | SE 10 | SE 10 | SE 10 | SSE 5 | SSE 5 | SSW 9 | SSE 6 | SSE 6 | SSW 8 |
2 | 3 | 2 | 5 | 12 | 4 | 4 | 4 | 8 | 18 | 15 | 15 | 15 | 2 | 2 | 16 | 28 | 12 | 14 | |
Swell 2 Height (m) Direction Period (s) | SE 11 | SE 8 | SE 11 | S 7 | SSE 10 | S 8 | SSE 10 | SSE 9 | SE 17 | SE 16 | SE 16 | SE 16 | SSE 15 | SE 15 | SE 11 | SE 5 | SSW 9 | SSW 9 | SE 6 |
4 | 2 | 5 | 1 | 10 | 1 | 9 | 8 | 11 | 10 | 10 | 10 | 22 | 8 | 18 | 7 | 16 | 15 | 5 | |
Swell 3 Height (m) Direction Period (s) | — | SE 11 | — | SE 7 | SE 19 | S 19 | SE 18 | SE 18 | SE 11 | S 5 | S 7 | S 7 | S 8 | SE 11 | S 9 | S 5 | SE 10 | SE 10 | SE 10 |
— | 4 | — | 2 | 15 | 7 | 12 | 12 | 5 | 2 | 1 | 1 | 1 | 5 | 7 | 4 | 16 | 16 | 16 | |
Wind waves Height (m) Direction Period (s) | SSW 4 | SSW 4 | S 4 | SSW 5 | — | SSW 6 | — | — | SSW 2 | ESE 3 | — | NE 3 | E 3 | — | SE 4 | SE 5 | — | NNE 3 | NNE 3 |
11 | 11 | 7 | 19 | — | 13 | — | — | 2 | 1 | — | 1 | 1 | — | 10 | 50 | — | 5 | 2 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 84 | 84 | 1433 | 84 | 24 | 26 | 57 | 57 | 252 | 30 | 57 | 45 | 57 | 24 | 30 | 7 | 0 | 24 | 57 |
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.










