Kugenuma Rivermouth Surf Break

Lat Long: 35.31° N 139.47° E

Kugenuma Rivermouth Surf Forecast and Surf Report

Issued: 2 am 16 Sep 2026 (local time)

Forecast update in  hr  min

Today's Kugenuma Rivermouth sea temperature is
27.1°C
1.2° 

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 15 Sep 2026:

  • Most powerful swell: Monday 21 Sep, 3AM (local time) - 10ft (3.0m), 13s period, SSE swell with 3,210 kJ wave energy.

Best Forecast Surf Conditions for Kugenuma Rivermouth this week:

The most powerful waves expected at Kugenuma Rivermouth in the next 16 days are 3.0m 13s and forecast to arrive on Monday (Sep 21) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 5s period and expected on Monday (Sep 21) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 3AM (Mon 21st Sep)10ft (3.0m) 13s

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


The Lowdown

Right, let’s have a look at what’s on the cards for the next couple of weeks. To be straight with you, it’s a grim start. We’re looking at a long, dry spell with hardly a wave worth paddling for. From now until the tail end of next week, the swell is tiny and the conditions are messy. You’re looking at a solid 10 days of flat or near-flat surf. The first real chance of anything decent doesn’t show up until the weekend of the 21st, and even then, it’s a bit of a wild card.

Let’s get into it. The only break on the table is Kugenuma Rivermouth. To start, Wednesday the 16th is a write-off. We’ve got a bit of wind but only 1ft of swell from the SE. It’s a no-go. That pattern holds through Thursday and Friday – we’re talking ankle-snappers at best. The wind is offshore, but when the swell is 0.3ft, it doesn’t matter.

Then we get to Saturday the 19th. Finally, something to talk about. The swell pushes up to 5ft from the SE, with a period of 13 seconds. The combined swell energy is moderate (778). It’s a decent bump, but the forecast has it as marginal. The wind is a fresh offshore from the N, so it’ll be clean. This is surfable, but it’s not a standout. Sunday the 20th is very similar, with the swell hitting 6ft (SSE) and energy jumping to 1170, which is moderate to strong. The wind stays offshore. These two days are the best of the first week, but the call is "marginal", so manage your expectations.

Now, Monday the 21st. The swell gets to 8ft from the SSE, with a period of 12 seconds. The energy is strong, at 1558. But the wind is a near gale from the N at 31 mph. That’s going to be a battle. For anyone but experts, this is too big and too windy. It’s more of a kite-surfing setup.

After that, we’re back to tiny dribble until Tuesday the 29th. That morning, we get a 4ft swell from the SSW with a 14-second period. The combined energy is moderate (506), with a moderate offshore wind from the NE. This is the first clean, proper groundswell of the outlook. The long period (14 seconds) means better shaped waves at the river mouth, but it might make it a bit straight. It’s a promising, but less certain, option this far out.

Wednesday the 1st of October is similar, with 2ft from the SSW and glassy conditions in the afternoon. It’s small but clean.

If you’re free, the standout is Saturday the 19th and Sunday the 20th. It’s not going to be epic, but it’s the most surfable window in the near-term. For the second week, keep an eye on Tuesday the 29th – that long-period SSW swell with offshore winds is the pick, but we’re a long way out. Water temperature is a touch warmer than normal at 81°.

Rusty.

Short Range Forecast

Heavy rain (total 63mm), heaviest during Wed night. Warm (max 21°C on Wed morning, min 19°C on Thu morning). Mainly strong winds.

Days 4-6 Weather Summary

Heavy rain (total 75mm), heaviest during Mon afternoon. Warm (max 25°C on Sat afternoon, min 21°C on Sat morning). Mainly near gales.

Wednesday
16
Thursday
17
Friday
18
Saturday
19
Sunday
20
Monday
21
Tuesday
22
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
0
0
0
0
0
0
0
2
2
2
1
2
2
1
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)
0.4
SE
7
0.4
SE
8
0.4
SE
8
0.2
SSE
8
0.2
SSE
9
0.1
E
10
0.1
S
12
0.1
SE
17
0.8
SE
14
1.5
SE
13
1.6
SE
13
1.6
SE
12
1.5
SE
12
1.7
SSE
12
3
SSE
13
2.3
SSE
12
1
SSE
11
0.6
SSE
9
0.5
SSE
8
0.4
SSE
8
0.4
SE
7
Wave Graph
Metric surfscale
Energy kJ
12
17
17
7
8
3
6
11
241
778
919
799
646
878
2890
1520
222
55
38
23
13
Wind (km/h)
20
NE
20
NNE
30
NNE
25
NNE
30
NNE
35
NNE
40
N
35
N
35
N
35
N
30
NNE
30
NNE
35
N
35
N
35
NNE
50
N
55
N
35
N
5
SSE
15
S
20
ESE
Wind State
off
off
off
off
off
off
off
off
off
off
off
off
off
off
off
off
off
cross-off
glassy
cross-on
cross
High Tide
6:53PM1.58m
8:36AM1.26m
7:20PM1.53m
9:56AM1.15m
7:47PM1.45m
8:14PM1.35m
4:05PM1.31m
9:47PM1.23m
3:49PM1.37m
1:05AM1.21m
3:58PM1.41m
2:32AM1.30m
Low Tide
12:46PM0.84m
1:50AM0.34m
1:04PM0.96m
2:44AM0.40m
1:07PM1.07m
4:02AM0.48m
6:00AM0.52m
8:47PM1.23m
7:36AM0.48m
9:09PM1.09m
8:38AM0.44m
9:33PM0.96m
heavy rain
heavy rain
heavy rain
cloud
part cloud
part cloud
cloud
part cloud
cloud
cloud
part cloud
mod rain
heavy rain
mod rain
mod rain
heavy rain
heavy rain
rain showers
clear
rain showers
rain showers
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:24
5:24
5:26
5:26
5:26
5:28
5:28
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
5:49
5:46
5:45
5:44
5:43
5:40
5:39
 mm
15
23
25
10
11
9
7
13
21
4
3
10
Temp °C
21
21
20
20
21
20
20
21
20
23
25
23
21
22
22
22
22
24
27
26
25
Feels °C
21
21
18
17
18
15
14
16
15
20
23
21
17
19
19
17
15
21
29
28
26
  • 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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