Kugenuma Rivermouth Surf Break

Kugenuma Rivermouth Surf Forecast and Surf Report

Lat Long: 35.31° N 139.47° E

Issued: 8 am 07 Jul 2026 (local time)

Forecast update in  hr  min

Today's Kugenuma Rivermouth sea temperature is
23.8° C

Slightly cooler than normal

Kugenuma Rivermouth surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Kugenuma Rivermouth surf forecast from 7 Jul 2026:

  • Best quality surf: Wednesday 8 Jul, 3AM (local time) - 4.5ft (1.3m), 16s period, SSE swell with glassy winds.
  • Most powerful swell: Saturday 11 Jul, 12AM (local time) - 7ft (2.2m), 16s period, SSW swell with 2,368 kJ wave energy.
  • Next surfable swell (1★+): Tuesday 7 Jul, 3PM (local time) - 3.5ft (1.0m), 15s period with SSE 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 Tuesday (Jul 07) at 3PM. The primary swell is predicted to be 1.0m and 15s period with a secondary swell of 0.3m and 20s. 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 2.2m 16s and forecast to arrive on Saturday (Jul 11) at 12AM. Winds are predicted to be onshore at the time the swell arrives.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3PM (Tue 7th Jul)3.5ft (1.0m) 15s
Best Surf 3AM (Wed 8th Jul)4.5ft (1.3m) 16s
Most Powerful12AM (Sat 11th Jul)7ft (2.2m) 16s

Table - best surf conditions forecast for Kugenuma Rivermouth over the next 16 days.


Updates in  hr  min  s Forecast update imminent

Alright folks, Rusty here. Let's have a look at what's on the menu for Kugenuma Rivermouth over the next couple of weeks. It's a bit of a mixed bag, so let's get into it.

The week starts off with a bit of hope. Tuesday morning, July 7th, sees a clean 2ft swell from the SSE with a very long 15-second period. The wind is light offshore from the NNE, so expect clean lines. The combined energy is weak (287), so it's not going to be a big day, but it's our best chance for a clean, small-wave session to kick things off. The water temp is sitting at 75°, which is just a shade cooler than average for this time of year—nothing to worry about.

Tuesday afternoon gets a little bigger at 3ft, but the wind swings cross-offshore from the east, keeping things workable with the wave energy climbing to moderate (518). Wednesday morning, July 8th, brings even more size at 5ft with that same long 16-second period, but the wind goes cross-shore from the ESE. The combined energy jumps to strong (1094), but conditions are described as marginal, so don't expect perfection.

From Wednesday afternoon right through most of next week, things go downhill. The wind locks in from the south, mostly onshore, and the swell fluctuates between 4ft and 7ft. The onshore breeze is going to chop things up, making it pretty average. The energy gets strong, peaking at 2699 on Friday afternoon, July 10th, with a 7ft S swell, but with 16 mph onshore wind, it’s going to be a messy, blown-out mess. Honestly, for a river-mouth setup, that combo looks more interesting for kite surfing than paddle surfing.

Then we hit a real dry spell. From Monday, July 13th, onwards, the swell drops right off. Monday morning has a small window of glassy 3ft SSW swell with no wind, but it's inconsistent and the energy is weak (191). After that, it's day after day of tiny surf, poor conditions, and onshore winds. This lull stretches right through to the end of the third week of July.

Now, there is a flicker of life on the horizon. On Sunday, July 19th, we see a bump back up to 6ft from the S with a 14-second period, pushing energy levels up to a strong 1426. But again, the wind is onshore from the south at 9 mph, so it'll be messy and choppy. It's too far out to get excited about, but it's something to keep an eye on.

To be honest, for this 16-day run, the only standout is that Tuesday morning, July 7th session at Kugenuma Rivermouth. It’s small, but clean and offshore. Everything else is a fight against the wind or waiting for the swell to come back. A tough outlook, but that's how it goes sometimes.

Rusty.

Short Range Forecast

Mostly dry. Warm (max 25°C on Tue afternoon, min 22°C on Tue night). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Warm (max 26°C on Sat afternoon, min 23°C on Fri night). Winds decreasing (fresh winds from the S on Sat afternoon, light winds from the SW by Sun night).

Tuesday
7
Wednesday
8
Thursday
9
Friday
10
Saturday
11
Sunday
12
Monday
13
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
2
3
3
3
2
2
2
1
2
2
0
1
1
0
1
1
0
0
1
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.7
SSE
15
1
SSE
15
0.8
SSE
16
1.4
SSE
16
1.5
SSE
16
1.6
SSE
14
1.4
SSE
14
1.4
SSE
14
1.7
S
15
1.5
S
14
2
S
16
2.2
SSW
16
2
SSW
17
1.9
SSW
16
1.6
SSW
16
1.4
SSW
15
1.2
SSW
14
0.9
SSW
12
0.8
SSW
12
1.1
S
11
0.5
SSW
11
Wave Graph
Metric surfscale
Energy kJ
201
443
328
1094
1055
980
799
799
1344
902
2027
2368
2215
1872
1245
892
585
245
161
313
69
Wind (km/h)
20
NNE
10
E
5
ESE
5
ESE
15
S
10
SSW
10
S
20
S
15
SSW
15
S
25
S
20
SSW
20
S
30
S
15
SSW
10
S
30
S
15
SSW
5
WSW
15
S
15
SSW
Wind State
off
cross-off
cross-off
cross
on
on
on
on
on
on
on
on
on
on
on
on
on
on
glassy
on
on
High Tide
10:05AM1.06m
10:14PM1.37m
12:11PM1.00m
10:59PM1.35m
3:26PM1.08m
11:50PM1.34m
4:34PM1.21m
00:46AM1.35m
5:09PM1.30m
1:43AM1.37m
5:36PM1.36m
2:36AM1.41m
5:58PM1.39m
Low Tide
3:25PM0.75m
5:51AM0.57m
4:12PM0.92m
7:08AM0.45m
5:54PM1.07m
8:11AM0.33m
7:54PM1.15m
9:03AM0.22m
9:11PM1.17m
9:46AM0.13m
10:00PM1.16m
10:23AM0.07m
10:36PM1.12m
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
cloud
cloud
clear
part cloud
part cloud
thunderstorm
cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:33
4:33
4:33
4:35
4:35
4:35
4:35
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
7:00
7:00
6:59
6:59
6:59
6:58
6:58
 mm
1
Temp °C
24
25
23
24
25
24
25
25
24
25
25
24
25
26
25
26
26
25
26
27
25
Feels °C
23
25
24
25
25
25
26
25
25
25
24
24
25
25
25
26
25
26
30
29
27
Swell 1
Height (m)
Direction
Period (s)
0.7
SSE
15
1
SSE
15
0.9
SSE
14
1.4
SSE
16
1.5
SSE
16
1.6
SSE
14
1.4
SSE
14
1.4
SSE
14
1.7
S
15
1.5
S
14
2
S
16
2.2
SSW
16
2
SSW
17
1.9
SSW
16
1.6
SSW
16
1.4
SSW
15
1.2
SSW
14
0.9
SSW
12
0.8
SSW
12
0.2
SSE
10
0.5
SSW
11
Energy kJ
201
443
328
1094
1055
980
799
799
1344
902
2027
2368
2215
1872
1245
892
585
245
161
9
69
Swell 2
Height (m)
Direction
Period (s)
0.6
SE
12
0.3
SSE
20
0.8
SSE
16
0.8
S
18
0.4
ESE
8
0.5
S
19
0.9
S
18
0.4
ESE
8
1
SSW
18
0.9
SSW
21
0.7
SE
10
0.2
SSE
10
0.4
SE
10
0.2
SSE
9
0.2
SSE
10
0.3
SE
10
0.1
SE
9
Energy kJ
86
75
310
422
25
184
509
21
655
672
100
10
28
8
9
16
3
Swell 3
Height (m)
Direction
Period (s)
0.2
WSW
6
0.4
ESE
8
0.1
SE
14
0.2
E
9
0.1
SE
13
0.1
SE
13
0.3
ESE
9
0.1
SE
12
Energy kJ
4
26
8
6
7
7
16
6
Wind waves
Height (m)
Direction
Period (s)
0.4
NNE
3
0.8
S
4
0.6
SSW
4
0.9
S
4
0.8
SSW
4
0.6
SSW
4
1.1
S
11
0.8
SSW
4
Energy kJ
3
18
11
27
24
14
313
25
Nearest Offshore or Glassy
Rating
(10 max)
2
3
3
4
4
3
4
4
4
4
4
4
4
4
3
1
4
1
1
2
1
Distance (km)
0
0
0
8
26
7
26
84
7
26
85
7
85
85
7
137
484
7
0
85
7
Best forecast wave conditions in Kanagawa
Rating
(10 max)
2
3
4
4
4
4
4
4
4
4
3
2
1
1
Best forecast wave conditions in Japan
Rating
(10 max)
4
4
4
4
5
5
4
4
5
5
9
9
9
6
5
5
4
4
4
3
3
Header Global
Rating
(10 max)
7
5
7
9
8
9
7
7
6
7
5
5
5
5
5
5
9
9
7
5
6
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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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