Surf Forecasts:
Kugenuma Rivermouth surf forecast from 5 Sep 2026:
- Best quality surf: Monday 7 Sep, 6PM (local time) - 10ft (3.0m), 10s period, S swell with cross-offshore winds.
- Most powerful swell: Monday 7 Sep, 3PM (local time) - 10ft (3.0m), 10s period, S swell with 1,889 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 6PM (local time) - 10ft (3.0m), 10s 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 (Sep 07) at 6PM. The primary swell is predicted to be 3.0m and 10s period. 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 3.0m 10s and forecast to arrive on Monday (Sep 07) at 3PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 4s period and expected on Sunday (Sep 06) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Mon 7th Sep) | 10ft (3.0m) 10s |
| Best Surf | 6PM (Mon 7th Sep) | 10ft (3.0m) 10s |
| Most Powerful | 3PM (Mon 7th Sep) | 10ft (3.0m) 10s |
Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s look at the next couple of weeks for the local zone. It’s a lean stretch, no doubt about it. There’s a solid pulse of swell coming through early next week, but the conditions are a real mixed bag around it. Most of the time, the surf is tiny or the wind is messing it up, so you’ll need to pick your moments.
The first real hope is Monday, September 7th. The morning brings a 7ft south swell, but it’s coming in with a light onshore. The energy is massive, but the wind is a problem, and the forecast is calling it marginal. The afternoon gets even bigger, hitting 10ft, but the onshore wind picks up, making it a messy, poor option. That’s expert-only territory if it’s even rideable.
The standout window is Tuesday, September 8th. The morning is the real gem. We’ve got a 5ft south swell, clean as a whistle with glassy conditions. The energy is solid, and the forecast is expecting very good surf. That’s the one to circle. The afternoon holds up okay too, dropping to 4ft with a clean offshore wind, but the morning is the clear winner.
Wednesday, September 9th, is a tease. The morning is a bit ugly with a 7ft south swell and a light cross-on. But the afternoon turns it around – same 7ft swell, but the wind goes glassy. That’s another very good session if you can wait.
After that, it’s a long dry spell. From Thursday the 10th through the end of the forecast on September 20th, the swell drops to tiny, mostly under 2ft, with consistent offshore winds but no real wave energy. The energy readings are all low. It’s a full-on lull, and there’s nothing to recommend.
For the standout, you’ve got to go with Kugenuma Rivermouth on Tuesday morning, September 8th. The 5ft south swell, glassy conditions, and solid energy will have it clean and fun. The wind is light offshore later in the day, but the morning glass is the call. Be aware that this spot is often crowded, so get there early.
Keep your eyes on Wednesday afternoon as a backup. Once we get past that, the water is a touch warmer than average for this time of year, but that won’t help the lack of waves.
Rusty.
Short Range ForecastHeavy rain (total 234mm), heaviest during Sun night. Warm (max 25°C on Mon morning, min 21°C on Sat night). Winds decreasing (strong winds from the N on Sun night, calm by Mon night). | Days 4-6 Weather SummaryHeavy rain (total 115mm), heaviest during Wed afternoon. Warm (max 25°C on Tue morning, min 17°C on Thu night). Winds increasing (calm on Tue morning, fresh winds from the N by Thu afternoon). | ||||||||||||||||||||
Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | |||||||||||||||
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) | SSW 9 | SSW 9 | SSW 8 | SE 8 | SSE 8 | SE 8 | S 10 | S 10 | S 10 | S 10 | SSE 9 | S 9 | S 10 | S 10 | S 9 | S 9 | S 9 | S 8 | S 8 | S 8 | S 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 50 | 27 | 14 | 10 | 12 | 458 | 928 | 1889 | 792 | 530 | 254 | 181 | 761 | 715 | 367 | 155 | 95 | 49 | 21 | 18 | 18 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | off | off | off | on | on | glassy | glassy | off | off | cross-on | glassy | off | off | off | off | off | off | off |
High Tide | 9:04PM1.32m | 4:27PM1.34m | 11:39PM1.24m | 4:24PM1.40m | 1:50AM1.27m | 4:34PM1.43m | 2:58AM1.36m | 4:45PM1.45m | 3:46AM1.44m | 4:57PM1.47m | 4:26AM1.51m | 5:10PM1.49m | |||||||||
Low Tide | 7:15AM0.47m | 9:04PM1.21m | 8:27AM0.40m | 9:35PM1.10m | 9:17AM0.35m | 9:58PM0.98m | 9:55AM0.33m | 10:20PM0.85m | 10:27AM0.35m | 10:42PM0.73m | 10:54AM0.39m | 11:05PM0.60m | |||||||||
 |  |  | |  |  | |  |  | | | |  | | | | |  | | |  | |
 | 5:16 | — | — | 5:16 | — | — | 5:18 | — | — | 5:18 | — | — | 5:18 | — | — | 5:20 | — | — | 5:20 | — | — |
 | — | 6:04 | — | — | 6:02 | — | — | 6:01 | — | — | 6:00 | — | — | 5:59 | — | — | 5:57 | — | — | 5:55 | — |
mm | 4 | — | — | 1 | 15 | 152 | 34 | 27 | 1 | 4 | 2 | 22 | 6 | 30 | 17 | 20 | 8 | 6 | 1 | 2 | — |
Temp °C | 22 | 23 | 23 | 23 | 22 | 22 | 25 | 25 | 25 | 25 | 24 | 23 | 24 | 24 | 21 | 20 | 20 | 19 | 18 | 19 | 20 |
Feels °C | 24 | 24 | 22 | 19 | 19 | 19 | 28 | 27 | 30 | 28 | 26 | 26 | 27 | 28 | 19 | 18 | 18 | 16 | 15 | 17 | 20 |
Swell 1 Height (m) Direction Period (s) | SSW 9 | SSW 9 | SSW 8 | SE 8 | SSE 8 | SSE 9 | SE 11 | — | S 10 | S 10 | SSE 9 | S 9 | E 17 | E 16 | S 9 | S 9 | S 9 | S 8 | S 8 | S 8 | S 8 |
| kJ | 50 | 27 | 14 | 10 | 12 | 211 | 5 | — | 792 | 530 | 254 | 181 | 6 | 5 | 367 | 155 | 95 | 49 | 21 | 18 | 18 |
Swell 2 Height (m) Direction Period (s) | SE 9 | ESE 7 | SE 6 | SSW 8 | ESE 8 | NNE 4 | — | — | E 8 | SSW 11 | SSW 10 | SSW 10 | E 17 | — | E 16 | ESE 11 | ESE 11 | E 16 | SE 10 | SE 10 | S 9 |
| kJ | 12 | 4 | 6 | 7 | 6 | 10 | — | — | 13 | 123 | 58 | 139 | 6 | — | 5 | 11 | 11 | 5 | 4 | 4 | 2 |
Swell 3 Height (m) Direction Period (s) | SE 9 | SE 8 | SE 8 | — | S 8 | NW 5 | — | — | — | — | E 9 | SSW 13 | — | — | SE 11 | E 15 | E 8 | SE 10 | E 14 | S 8 | E 10 |
| kJ | 12 | 3 | 3 | — | 1 | 1 | — | — | — | — | 7 | 17 | — | — | 5 | 4 | 5 | 15 | 4 | 1 | 2 |
Wind waves Height (m) Direction Period (s) | — | NE 2 | ENE 3 | NE 4 | NE 4 | SE 8 | S 10 | S 10 | — | — | — | — | S 10 | S 10 | NNE 3 | NE 3 | NE 3 | NNE 3 | NNE 3 | NNE 3 | NNE 3 |
| kJ | — | 1 | 3 | 21 | 18 | 458 | 928 | 1889 | — | — | — | — | 761 | 715 | 10 | 5 | 5 | 7 | 3 | 3 | 3 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 45 | 480 | 545 | 545 | 13 | 7 | 7 | 0 | 0 | 0 | 0 | 7 | 0 | 0 | 545 | 30 | 252 | 140 | 130 | 63 |
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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