Kugenuma Rivermouth Surf Break

Lat Long: 35.31° N 139.47° E

Kugenuma Rivermouth Surf Forecast and Surf Report

Issued: 8 am 06 Sep 2026 (local time)

Forecast update in  hr  min

Today's Kugenuma Rivermouth sea temperature is
28.2°C
1.7° 

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 6 Sep 2026:

  • Best quality surf: Monday 7 Sep, 12AM (local time) - 6ft (1.9m), 8s period, SE swell with offshore winds.
  • Most powerful swell: Monday 7 Sep, 12PM (local time) - 8ft (2.4m), 9s period, S swell with 909 kJ wave energy.
  • Next surfable swell (1★+): Monday 7 Sep, 12AM (local time) - 6ft (1.9m), 8s 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 Monday (Sep 07) at 12AM. The primary swell is predicted to be 1.9m and 8s period with a secondary swell of 1.0m and 8s. Another secondary swell of 0.7m and 9s is also forecast. 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 2.4m 9s and forecast to arrive on Monday (Sep 07) at 12PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 4s period and expected on Sunday (Sep 06) at 6PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+)12AM (Mon 7th Sep)6ft (1.9m) 8s
Best Surf12AM (Mon 7th Sep)6ft (1.9m) 8s
Most Powerful12PM (Mon 7th Sep)8ft (2.4m) 9s

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


The Lowdown

Alright, let's get real about the next couple of weeks here at Kugenuma Rivermouth. Honestly, I'm looking at this forecast and it's a bit of a heartbreaker. We're coming off a pretty flat spell, and the truth is, there's just nothing on the cards that's going to get the stoke levels up. We've got a good 16-day window ahead, but it's a long, lean one.

The first real chance of anything rideable, and I'm using that word loosely, is on Monday the 7th. A southerly swell pushes in, but it comes with a side of messy weather and a strong cross-onshore wind. The swell jumps up to 7ft, with a combined energy of 710. That's a moderate amount of energy, but the wind is just going to tear it to pieces. It's lumpy, it's choppy, and it's not the kind of day you'd paddle out for fun. The afternoon sees it get even bigger, with 7ft of S swell and a combined energy of 1330. That's a lot of water moving, but with a strong onshore wind, this is more of a windswell mess for the experts only, if anyone. This is the kind of setup that's more interesting for the kite surfers than us paddle guys.

Things settle down a bit, but not into quality. Tuesday the 8th morning has a 3ft SSW swell, weak energy at 292, and still onshore. Not good. The real tease of the whole outlook comes Tuesday afternoon. We get a drop to 3ft from the SSE, but the wind swings around to the north at 9 mph, going offshore. The report says "expect good surf conditions," and while the score is low, that offshore wind is a major positive. The swell is short period at 8 seconds, so it won't be powerful, but it'll be clean. For a brief moment, you might find a fun little bank with a friend. This is the only whisper of a window in the whole run.

After that, it's a long, slow fade. From Wednesday the 9th all the way through to Monday the 21st, we're looking at tiny waves. Most days the swell is under 2ft, with combined energy values dropping from 470 down to single digits. The wind is predominantly offshore for much of that time, which is the only saving grace, but there's just no energy in the water to make it worthwhile. We get a couple of days of glassy conditions on the 16th, with a 0.7ft wave, but it's just flat. This is a classic blank run for this area. The water is a touch warmer than normal at 83°, but that's not going to help the waves.

So, to put it straight: there's no standout here. The best on offer is a very short window on Tuesday afternoon, the 8th, for a clean, knee-high to maybe waist-high wave if you're lucky. But it's a fleeting moment. For the rest of the 16 days, leave the board in the car and save your energy. The forecast can always change, but right now, it's a waiting game.

Rusty

Short Range Forecast

Heavy rain (total 274mm), heaviest during Sun night. Warm (max 26°C on Mon morning, min 21°C on Sun morning). Winds decreasing (strong winds from the SE on Sun night, calm by Tue night).

Days 4-6 Weather Summary

Moderate rain (total 10mm), heaviest on Wed night. Warm (max 28°C on Wed morning, min 19°C on Wed night). Mainly fresh winds.

Sunday
6
Monday
7
Tuesday
8
Wednesday
9
Thursday
10
Friday
11
Saturday
12
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
3
0
0
0
0
2
3
0
1
2
1
1
0
0
0
0
0
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)
0.2
SSE
8
0.4
SE
8
1.9
SE
8
2.1
S
9
2.2
S
9
1.7
S
9
0.9
SSE
9
0.9
SSE
9
1.9
S
10
1.4
SSW
10
1.7
SSW
9
1.6
S
9
1.1
S
8
0.9
S
8
0.6
S
8
0.5
S
7
0.5
S
8
0.5
S
8
0.4
S
8
0.4
S
8
0.3
SSW
8
Wave Graph
Metric surfscale
Energy kJ
7
18
475
710
805
476
144
131
660
341
456
422
173
104
42
27
28
30
19
18
13
Wind (km/h)
35
NNE
35
NNE
10
NE
35
S
25
SSW
20
SSW
20
SSW
15
N
5
SW
20
SW
15
SW
25
NNE
20
N
15
NNE
15
NNE
15
NNE
20
NNE
15
NNE
20
NNE
20
NE
15
NE
Wind State
off
off
off
cross-on
on
on
on
off
glassy
on
cross-on
off
off
off
off
off
off
off
off
off
off
High Tide
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
5:03AM1.54m
5:25PM1.52m
Low Tide
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
11:18AM0.46m
11:30PM0.48m
mod rain
heavy rain
heavy rain
thunderstorm
thunderstorm
mod rain
heavy rain
light rain
part cloud
part cloud
thunderstorm
mod rain
light rain
cloud
light rain
cloud
part cloud
part cloud
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:16
5:18
5:18
5:18
5:20
5:20
5:20
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:02
6:01
6:00
5:59
5:57
5:55
5:54
 mm
6
42
169
26
3
8
19
1
1
7
1
1
Temp °C
21
21
25
26
26
26
24
24
26
28
28
21
21
21
21
21
22
22
23
24
24
Feels °C
17
18
22
25
27
28
26
26
29
30
31
18
20
20
22
22
22
23
23
24
25
  • 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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