
Surf Forecasts:
Kugenuma Rivermouth surf forecast from 4 Aug 2026:
- Best quality surf: Wednesday 5 Aug, 3AM (local time) - 7ft (2.1m), 16s period, SE swell with offshore winds.
- Most powerful swell: Wednesday 5 Aug, 12PM (local time) - 7.5ft (2.3m), 15s period, SSE swell with 2,432 kJ wave energy.
- Next surfable swell (1★+): Wednesday 5 Aug, 3AM (local time) - 7ft (2.1m), 16s 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 Wednesday (Aug 05) at 3AM. The primary swell is predicted to be 2.1m and 16s period with a secondary swell of 0.2m and 13s. 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 2.3m 15s and forecast to arrive on Wednesday (Aug 05) at 12PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 4s period and expected on Wednesday (Aug 05) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Wed 5th Aug) | 7ft (2.1m) 16s |
| Best Surf | 3AM (Wed 5th Aug) | 7ft (2.1m) 16s |
| Most Powerful | 12PM (Wed 5th Aug) | 7.5ft (2.3m) 15s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s have a look at what’s comin’ down the line for Kugenuma Rivermouth.
We’ve got a solid run of surf kickin’ off from Tuesday the 4th of August and stretchin’ right through the first week, but hookin’ in a bit of punch early on. The water temp is sittin’ at 83°, which is a touch warmer than normal for this time of year – you’ll notice that bathwater feel right away.
Tuesday morning starts with a clean 5ft SE swell, period hangin’ at a very long 17 seconds. That’s proper groundswell energy, and combined is pumpin’ at 1098 – moderate-to-strong, so expect some good lines. The wind is a fresh 19 mph offshore from the NE, keepin’ it glassy. This is a rivermouth setup, and with that long period the waves might unload a bit straight on the banks, but you’ll find some wedgy corners. Afternoon sees the swell bump to 6ft SE, 16-second period, still clean, though a touch more cross-off. Not massive, but clean and fun for a Tuesday arvo session.
Wednesday the 5th is a standout. Morning brings 7ft SSE swell, 16-second period, and combined energy jumps to 2379 – strong. Wind is NNE at 16 mph offshore. These are proper lines, and at this size it’s gettin’ into intermediate-to-advanced territory – beginners might find it a handful. Clean and wedgy at the mouth. Afternoon holds at 8ft SSE, 15-second period, still clean cross-off. Best of the week right here.
Thursday the 6th keeps the swell around 7ft SSE but the period drops a little to 14 seconds – still a solid groundswell, just a touch less juice. Clean in the morning, light cross-shore by the arvo. Consistency is there but it’s not all-day perfection.
Friday the 7th morning is another cracker: 7ft S swell, 15-second period, and the wind is light offshore at 6 mph from the NE. Combined energy is 2032 – strong. This is excellent for experienced surfers, with clean, lined-up waves. Afternoon the wind swings cross-on and it gets a bit choppy, so make the most of the morning.
The weekend (Sat 8th and Sun 9th) sees a drop-off. Saturday morning has 5ft SSW swell, 14-second period, but light cross-shore wind and some rain showers – it’s surfable but not special. Sunday morning is cleaner with 5ft SSW swell and gentle offshore, but the size is fadin’.
Then we hit a dry stretch. From Monday the 10th through the rest of the second week, the swell drops under 3ft and keeps sinkin’ to 1ft by the 19th. Winds are often strong offshore (19 to 31 mph) which will be blown-out and hard work, then later light but tiny. There’s nothin’ worth paddlin’ out for from the 10th onward – a proper gap of about 10 days with no real options. The early pulse is your window, and it’s a beauty.
For the standout, lock in Wednesday the 5th – that 7ft to 8ft SSE groundswell with offshore wind is the best of the forecast. Friday morning the 7th is your backup highlight. Crowds are often a factor at Kugenuma Rivermouth, so expect company on those clean days.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Thu night. Warm (max 30°C on Thu morning, min 23°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Fri night. Warm (max 30°C on Fri morning, min 24°C on Sun night). Winds increasing (light winds from the E on Fri night, fresh winds from the NNE by Sun night). | ||||||||||||||||||||
Tuesday 4 | Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | |||||||||||||||
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) | SE 17 | SE 16 | SE 16 | SSE 16 | SSE 15 | SSE 14 | SSE 14 | S 14 | S 14 | S 15 | S 15 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 16 | SSW 16 | SSW 16 | SW 15 |
Wave Graph | |||||||||||||||||||||
1094 | 1464 | 2107 | 2379 | 2414 | 1835 | 1665 | 2012 | 1972 | 1881 | 1739 | 1189 | 1060 | 1030 | 874 | 899 | 534 | 674 | 499 | 425 | 171 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | cross-off | off | off | cross-off | off | cross-off | cross | cross-off | cross-off | cross-on | cross | cross | on | cross-off | cross-off | cross-off | off | off | off | off |
High Tide | 8:29PM1.48m | 9:35AM1.12m | 9:01PM1.45m | 11:35AM1.03m | 9:37PM1.40m | 10:28PM1.35m | 5:09PM1.29m | 11:56PM1.32m | 5:08PM1.37m | 1:34AM1.33m | 5:20PM1.42m | 2:44AM1.38m | |||||||||
Low Tide | 1:56PM0.69m | 3:24AM0.54m | 2:16PM0.86m | 4:41AM0.53m | 2:02PM1.01m | 6:19AM0.48m | 7:46AM0.40m | 8:22PM1.25m | 8:49AM0.30m | 9:37PM1.20m | 9:36AM0.23m | 10:13PM1.12m | |||||||||
4:52 | — | — | 4:52 | — | — | 4:52 | — | — | 4:54 | — | — | 4:54 | — | — | 4:56 | — | — | 4:56 | — | — | |
— | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:37 | — | |
mm | — | — | — | — | — | — | — | — | 2 | — | — | 3 | 1 | — | 1 | — | — | — | — | — | 2 |
Temp °C | 27 | 28 | 24 | 26 | 29 | 27 | 30 | 30 | 27 | 30 | 29 | 27 | 29 | 29 | 26 | 29 | 30 | 25 | 28 | 28 | 26 |
Feels °C | 24 | 25 | 22 | 25 | 30 | 29 | 32 | 32 | 31 | 32 | 31 | 30 | 32 | 30 | 29 | 29 | 29 | 23 | 25 | 24 | 22 |
Swell 1 Height (m) Direction Period (s) | SE 17 | SE 16 | SE 16 | SSE 16 | SSE 15 | SSE 14 | SSE 14 | S 14 | S 14 | S 15 | S 15 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 16 | SSW 16 | SSW 16 | SW 15 |
1094 | 1464 | 2107 | 2379 | 2414 | 1835 | 1665 | 2012 | 1972 | 1881 | 1739 | 1189 | 1060 | 1030 | 874 | 899 | 534 | 674 | 499 | 425 | 171 | |
Swell 2 Height (m) Direction Period (s) | E 14 | E 13 | — | — | — | — | E 10 | ESE 10 | ESE 10 | ESE 10 | SE 9 | SE 9 | ESE 12 | ESE 12 | ESE 12 | ESE 16 | SW 16 | SE 8 | SE 8 | SE 8 | S 13 |
4 | 3 | — | — | — | — | 53 | 114 | 111 | 151 | 263 | 297 | 13 | 14 | 30 | 48 | 267 | 35 | 17 | 10 | 125 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | E 15 | SE 17 | ESE 16 | SSE 8 | — | SSE 9 | ESE 13 | ESE 13 | S 13 | ESE 13 |
— | — | — | — | — | — | — | — | — | — | — | 4 | 12 | 25 | 114 | — | 31 | 17 | 18 | 31 | 17 | |
Wind waves Height (m) Direction Period (s) | NNE 3 | — | — | NNE 4 | — | — | — | — | — | — | — | — | — | — | — | — | SE 9 | ENE 3 | NE 4 | NE 3 | NNE 4 |
7 | — | — | 22 | — | — | — | — | — | — | — | — | — | — | — | — | 110 | 2 | 10 | 7 | 10 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 140 | 45 | 484 | 482 | 18 | 0 | 4 | 18 | 0 | 0 | 49 | 18 | 18 | 49 | 0 | 0 | 18 | 1024 | 2067 | 2057 | 130 |
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.











