Surf Forecasts:
Kugenuma Rivermouth surf forecast from 26 Jul 2026:
- Best quality surf: Sunday 2 Aug, 12PM (local time) - 1.5ft (0.4m), 15s period, SE swell with cross-offshore winds.
- Most powerful swell: Monday 3 Aug, 6AM (local time) - 2ft (0.6m), 15s period, ESE swell with 144 kJ wave energy.
- Next surfable swell (1★+): Sunday 2 Aug, 12PM (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 12PM. The primary swell is predicted to be 0.4m and 15s period with a secondary swell of 0.2m and 10s. 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 0.6m 15s and forecast to arrive on Monday (Aug 03) at 6AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 2s period and expected on Monday (Jul 27) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12PM (Sun 2nd Aug) | 1.5ft (0.4m) 15s |
| Best Surf | 12PM (Sun 2nd Aug) | 1.5ft (0.4m) 15s |
| Most Powerful | 6AM (Mon 3rd Aug) | 2ft (0.6m) 15s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s break down what’s happening at Kugenuma Rivermouth.
For the next week or so, it’s mostly flat and disappointing – tiny waves under 2 ft with short-period slop and winds that just mess everything up. The water temp is around 81°, which feels a touch warmer than usual for this time of year, but it doesn’t make the waves any better. We’re looking at a dry spell through the end of July.
Things start to perk up around Monday the 3rd of August. A moderate offshore breeze from the NNE helps clean things up, and the swell climbs to about 2 ft from the SE, with a long 16-second period. The combined swell energy hits 274 (moderate). Long period groundswell often works well at a river mouth like this, so it’s starting to look more promising.
The best bet for the everyday surfer is Wednesday the 5th of August in the morning. Glassy conditions with the swell running 4 ft from the SE, period 17 seconds, and combined energy up to 640 (moderate to strong). It's clean, not too big, and should offer a fun session for most.
By Friday the 7th of August, it gets serious. The morning serves up 10 ft of swell from the SE with an 18-second period. Combined energy is a massive 4642 (very strong). With a light cross-offshore wind, it will be very clean – this is the standout of the entire forecast, but it's strictly for experts. The afternoon sees it push even bigger to 12 ft, but with cross-onshore winds, it may get messy.
Saturday the 8th of August sees a monster 18 ft swell in the morning from the SSE, period 18 seconds, and combined energy of 17516 (very strong). Glassy conditions, but this is way too big for this break – dangerous for anyone but the most advanced. The afternoon stays around 18 ft with onshore winds, so rough.
From Sunday the 9th through Monday the 10th, the swell drops from 13 ft to about 7 ft, but winds are onshore and quality suffers. By Tuesday the 11th, it's back down to 3 ft and fading.
So, the early days are a bust. Wednesday the 5th morning is your best window if you want clean, manageable waves. But if you’re an expert looking for a challenge, Friday the 7th morning is the one to circle – massive, clean, but not for the faint-hearted.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Mon night. Warm (max 28°C on Mon afternoon, min 24°C on Mon morning). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Thu night. Warm (max 28°C on Thu morning, min 25°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Monday 27 | Tuesday 28 | Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | |||||||||||||||
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 10 | SE 10 | SE 10 | SE 10 | SE 10 | SW 4 | S 6 | SSW 7 | SSW 7 | SSW 7 | SSW 7 | S 7 | SSW 7 | SSW 7 | SSW 7 | SE 11 | SE 11 | SE 17 | ESE 15 | SE 15 | SE 14 |
Wave Graph  | |||||||||||||||||||||
 kJ | 16 | 16 | 16 | 15 | 15 | 34 | 29 | 35 | 29 | 21 | 18 | 9 | 5 | 5 | 4 | 4 | 4 | 12 | 23 | 54 | 103 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | glassy | cross-off | cross-on | on | off | glassy | on | cross-off | cross-off | on | cross | cross | cross | cross | cross-off | cross-on | cross-off | off | cross | off |
High Tide | 5:41PM1.41m | 3:05AM1.42m | 5:56PM1.43m | 3:53AM1.46m | 6:11PM1.44m | 4:37AM1.50m | 6:27PM1.45m | 5:20AM1.52m | 6:46PM1.47m | 6:02AM1.50m | 7:08PM1.49m | 6:46AM1.45m | 7:32PM1.50m | ||||||||
Low Tide | 10:02AM0.15m | 10:26PM1.13m | 10:37AM0.11m | 10:54PM1.05m | 11:09AM0.11m | 11:20PM0.96m | 11:38AM0.13m | 11:49PM0.86m | 12:07PM0.19m | 00:21AM0.76m | 12:35PM0.28m | 00:57AM0.67m | 1:03PM0.40m | 1:38AM0.60m | |||||||
 | |  | |  |  |  |  | | | | | | |  | | | | | |  | |
 | 4:46 | — | — | 4:47 | — | — | 4:47 | — | — | 4:48 | — | — | 4:48 | — | — | 4:50 | — | — | 4:50 | — | — |
 | — | 6:50 | — | — | 6:49 | — | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — |
mm | — | — | 1 | — | 1 | 1 | — | 1 | 1 | — | — | 3 | — | 1 | — | — | — | 1 | — | 1 | 5 |
Temp °C | 26 | 28 | 25 | 26 | 27 | 26 | 28 | 28 | 27 | 28 | 28 | 26 | 27 | 27 | 26 | 27 | 28 | 26 | 28 | 28 | 26 |
Feels °C | 27 | 31 | 28 | 28 | 29 | 29 | 30 | 29 | 30 | 30 | 29 | 29 | 31 | 30 | 29 | 30 | 32 | 29 | 31 | 30 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 8 | SSW 8 | SSW 8 | SSW 9 | SSW 9 | SSW 4 | S 6 | SE 9 | SSW 7 | SSW 7 | SE 10 | S 7 | SSW 7 | SSW 7 | SSW 7 | SW 7 | SE 9 | SE 9 | ESE 15 | SE 15 | SE 14 |
| kJ | 14 | 14 | 14 | 15 | 15 | 5 | 29 | 3 | 29 | 21 | 4 | 9 | 5 | 5 | 4 | 2 | 3 | 3 | 23 | 54 | 103 |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 10 | SE 10 | SE 10 | SE 10 | SSW 8 | SE 10 | SE 12 | SE 10 | SE 10 | SE 12 | SE 9 | SSE 5 | SE 9 | SE 10 | SE 8 | S 8 | SE 12 | SE 9 | SE 10 | SSE 10 |
| kJ | 16 | 16 | 16 | 15 | 15 | 14 | 4 | 6 | 4 | 4 | 6 | 3 | 2 | 3 | 4 | 3 | 1 | 6 | 3 | 4 | 9 |
Swell 3 Height (m) Direction Period (s) | SE 14 | SE 14 | SE 13 | SE 13 | SE 13 | SE 10 | SE 13 | — | SE 12 | SE 12 | S 8 | S 10 | SE 9 | S 11 | — | SE 11 | SE 11 | SE 17 | S 7 | SE 7 | S 9 |
| kJ | 8 | 8 | 7 | 7 | 7 | 4 | 7 | — | 6 | 6 | 1 | 2 | 3 | 3 | — | 4 | 4 | 12 | 1 | 2 | 1 |
Wind waves Height (m) Direction Period (s) | NE 2 | — | ESE 3 | — | — | SW 4 | — | SSW 7 | — | — | SSW 7 | — | — | S 2 | — | — | S 2 | S 3 | — | — | — |
| kJ | 1 | — | 2 | — | — | 34 | — | 35 | — | — | 18 | — | — | 1 | — | — | 1 | 1 | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 57 | 24 | 30 | 24 | 85 | 2 | 24 | 85 | 57 | 57 | 85 | 82 | 82 | 82 | 63 | 69 | 57 | 57 | 45 | 45 | 0 |
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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