Surf Forecasts:
Kugenuma Rivermouth surf forecast from 20 Jul 2026:
- Best quality surf: Monday 27 Jul, 9AM (local time) - 1.5ft (0.5m), 11s period, S swell with glassy winds.
- Most powerful swell: Monday 27 Jul, 9PM (local time) - 2ft (0.6m), 10s period, S swell with 80 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 9AM (local time) - 1.5ft (0.5m), 11s period with S 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 Monday (Jul 27) at 9AM. The primary swell is predicted to be 0.5m and 11s period with a secondary swell of 0.4m and 4s. Another secondary swell of 0.6m and 4s 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 0.6m 10s and forecast to arrive on Monday (Jul 27) at 9PM. Winds are predicted to be glassy at the time the swell arrives.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9AM (Mon 27th Jul) | 1.5ft (0.5m) 11s |
| Best Surf | 9AM (Mon 27th Jul) | 1.5ft (0.5m) 11s |
| Most Powerful | 9PM (Mon 27th Jul) | 2ft (0.6m) 10s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here, talking in feet and Fahrenheit now. Let's get into it.
Right off the bat, the forecast for Kugenuma Rivermouth is a real slow burner. From the 20th to the 26th, we're looking at a long stretch of tiny, weak waves. Heights are barely 0.7 ft to 2 ft, with combined swell energy mostly in the teens or low twenties. That’s just not enough to bother with. The water temp is about 79°, which is pretty normal for the season, so at least it's comfortable for a dip.
The first real chance comes on the morning of Monday, July 27th. The wind is glassy out of the SW, with a 2 ft S swell coming in at 11 seconds. The combined energy is still weak at 92, and the report says "surfable waves but very ordinary conditions," so it's not a classic, but that glassy wind is a big win for clean lines. That morning is your best bet in the first week.
The one true standout in this whole 16-day window is the morning of Wednesday, July 29th. The conditions are glassy, with a 3 ft SSW swell and a 12-second period. The combined energy hits a moderate 241, and the report says "expect good surf conditions." That's the one to shoot for. The glassy wind and the longer period will give the waves plenty of shape and push, and for a beginner-friendly rivermouth, it's about as good as it gets. The swell is small enough to be fun but has enough energy to get you moving.
After that, the window closes again. The morning of Friday, July 31st, has glassy conditions with a 4 ft SW swell, but the period is a short 7 seconds, so the waves will be weak and messy. The energy is moderate at 285, but it's just not the same quality.
From August 1st through the 4th, the forecast is a total flat spell. Tiny swells (0.7 ft to 2 ft) and onshore winds. Don't bother. So, mark your calendar for the morning of the 29th. That's the only real standout in the whole run.
Rusty.
Short Range ForecastMostly dry. Warm (max 31°C on Thu morning, min 27°C on Mon night). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 54mm), heaviest during Fri night. Warm (max 31°C on Thu afternoon, min 24°C on Sat night). Wind will be generally light. | |||||||||||||||||||
Mon 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | ||||||||||||||
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) | SSE 8 | SSE 8 | SSE 8 | ESE 11 | SW 4 | SSW 4 | SSW 3 | SSW 4 | SSE 10 | SSW 6 | SSE 10 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SSE 15 | SE 15 | S 4 | SE 11 |
Wave Graph  | ||||||||||||||||||||
 kJ | 7 | 7 | 6 | 12 | 21 | 4 | 5 | 10 | 15 | 10 | 12 | 12 | 11 | 18 | 15 | 15 | 22 | 8 | 12 | 20 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | glassy | on | glassy | cross-on | on | on | cross-off | on | glassy | cross-off | cross-on | glassy | cross-off | on | cross-off | cross-off | on | on |
High Tide | 8:44PM1.45m | 9:09AM1.15m | 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 | ||||||||
Low Tide | 3:19AM0.62m | 2:35PM0.72m | 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 | |||||||||
 |  | |  | | | | | | |  | |  |  | | | | | |  | |
 | — | — | 4:41 | — | — | 4:41 | — | — | 4:43 | — | — | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — |
 | 6:54 | — | — | 6:53 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — |
mm | — | — | — | — | — | — | — | — | — | — | 4 | — | 9 | 32 | — | 2 | 7 | — | — | — |
Temp °C | 29 | 29 | 30 | 29 | 29 | 29 | 29 | 29 | 31 | 31 | 29 | 29 | 29 | 25 | 28 | 28 | 25 | 26 | 27 | 26 |
Feels °C | 31 | 33 | 35 | 32 | 33 | 34 | 33 | 33 | 36 | 35 | 33 | 33 | 33 | 28 | 32 | 31 | 29 | 30 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | SSE 8 | SSE 8 | SSW 4 | SSE 8 | SSW 4 | SSW 4 | SE 8 | SE 11 | SSW 5 | SSE 10 | S 5 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SE 10 | SE 15 | SE 15 | S 9 |
| kJ | 7 | 7 | 3 | 6 | 10 | 4 | 2 | 5 | 5 | 10 | 2 | 8 | 8 | 18 | 15 | 15 | 15 | 8 | 8 | 16 |
Swell 2 Height (m) Direction Period (s) | S 7 | S 7 | SSE 8 | E 11 | SE 8 | SE 8 | SE 11 | SE 7 | SSE 10 | S 8 | SSE 10 | S 5 | SE 17 | SE 16 | SE 16 | SE 16 | SSE 15 | SE 11 | SE 11 | SE 11 |
| kJ | 1 | 1 | 6 | 2 | 2 | 2 | 5 | 2 | 10 | 1 | 9 | 2 | 11 | 10 | 10 | 10 | 22 | 5 | 5 | 18 |
Swell 3 Height (m) Direction Period (s) | SE 11 | E 11 | E 11 | ESE 11 | SE 11 | SE 11 | SE 8 | S 6 | SE 19 | S 19 | SE 18 | SE 18 | SE 11 | SW 7 | — | S 7 | S 8 | SE 9 | SE 9 | SSE 14 |
| kJ | 5 | 2 | 2 | 12 | 4 | 4 | 2 | 1 | 15 | 7 | 12 | 12 | 5 | 2 | — | 1 | 1 | 3 | 3 | 20 |
Wind waves Height (m) Direction Period (s) | SSW 3 | SSW 4 | SW 4 | S 4 | SW 4 | — | SSW 3 | SSW 4 | — | SSW 6 | — | — | S 5 | SE 3 | SE 4 | SSE 2 | SSE 3 | S 3 | S 4 | S 4 |
| kJ | 3 | 5 | 5 | 6 | 21 | — | 3 | 10 | — | 10 | — | — | 2 | 2 | 3 | 1 | 2 | 1 | 12 | 11 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 85 | 84 | 84 | 1420 | 84 | 84 | 84 | 84 | 63 | 85 | 61 | 57 | 57 | 24 | 57 | 24 | 57 | 24 | 26 | 84 |
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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