Kuminatu Surf Break

Lat Long: 35.12° N 140.24° E

Kuminatu Surf Forecast and Surf Report

Issued: 8 am 15 Jul 2026 (local time)

Forecast update in  hr  min

Today's Kuminatu sea temperature is
25.2° C
0.0° 

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


Kuminatu surf forecast from 15 Jul 2026:

  • Best quality surf: Sunday 19 Jul, 3AM (local time) - 4ft (1.2m), 9s period, E swell with glassy winds.
  • Most powerful swell: Tuesday 21 Jul, 3PM (local time) - 4.5ft (1.4m), 12s period, ENE swell with 532 kJ wave energy.
  • Next surfable swell (1★+): Sunday 19 Jul, 3AM (local time) - 4ft (1.2m), 9s period with E swell.

Best Forecast Surf Conditions for Kuminatu this week:

The surf forecast for Kuminatu over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Jul 19) at 3AM. The primary swell is predicted to be 1.2m and 9s period with a secondary swell of 0.5m and 8s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Kuminatu in the next 16 days are 1.4m 12s and forecast to arrive on Tuesday (Jul 21) at 3PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 4s period and expected on Wednesday (Jul 22) at 6AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Sun 19th Jul)4ft (1.2m) 9s
Best Surf 3AM (Sun 19th Jul)4ft (1.2m) 9s
Most Powerful 3PM (Tue 21st Jul)4.5ft (1.4m) 12s

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


The Lowdown

Alright, let’s talk about Kuminatu. The combo of wind and swell angles just isn’t lining up for most of the outlook. The window opens with a long stretch of poor conditions, with the first few days offering nothing but choppy, weak waves. The combined energy of all swells is low, sitting around 122 on Wednesday morning, barely enough to keep your board wet. Winds are cross-onshore, and the water temp is 77°, which is spot on average for this time of year.

Wednesday and Thursday are a write-off – small, short-period swells, messy wind. The energy builds a bit by Friday and Saturday, but the wind stays onshore or cross-onshore, keeping it choppy. The combined swell energy climbs to 242 on Friday morning, but the “poor surf conditions” label tells the story.

The first real standout comes on Sunday, July 19th. Glassy conditions in the morning with a light SSE breeze, and the swell holds at 4ft from the east, with a period of 9 seconds. The combined energy hits 284 – moderate. It’s the only window where the forecast says “expect good surf conditions.” That’s the one to chase if you’re keen. The break is exposed and inconsistent, and it breaks rarely, so don’t expect a miracle, but when it’s on, it’s clean. The SSE wind is offshore, and that’s a major positive for those early hours.

Monday the 20th is marginal, with cross-onshore winds creeping back in. The energy stays moderate, but the texture gets bumpy. From Tuesday, July 21st, through to the end of the week, the swell picks up but the wind stays cross-onshore. The combined energy climbs into the 400s and 500s, but it’s all messy. On Wednesday the 22nd, a rain shower and a strong cross-offshore NE wind at 15 mph actually clean it up a bit – the wave comment says “clean” – but the swell is only 4ft and the period is 11 seconds, so it’s a so-so session.

The second week brings a major pulse of energy. From Sunday, July 26th, the swell jumps to 5ft, and by Monday the 27th it’s 8ft with combined energy over 2000 – that’s serious power. But the wind is still cross-onshore, and the wave comments are all “marginal” or “poor.” That’s a lot of water moving around with no good wind to handle it. The setup is more interesting for kite surfing than paddle surfing during those days.

The best of the whole outlook? That’s Thursday, July 30th. The swell hits 6ft from the ESE with a very long period of 15 seconds, and the combined energy is a massive 2426. The wind is glassy in the morning from the SSE, which is onshore but at 3 mph it’s almost nothing. This is a long-period groundswell, so Kuminatu’s beach break might get a bit straight, but with that energy and clean conditions, it’s worth the look. The downside: it’s inconsistent and rarely breaks, so you’ll need patience. Crowds are possible here – it’s exposed and can handle a crew when it’s on.

For the advanced surfers, Monday the 27th and Tuesday the 28th have 8ft and 4ft swells, but the wind is still messy. The 8ft is too big for beginners, and even for experts the chop makes it a grind.

Overall, the best window is the morning of Sunday, July 19th, and the big pulse on July 30th is promising but less certain so far out. If you’re after a clean peak, aim for the 19th. The rest is a waiting game.

Rusty.

Short Range Forecast

Light rain (total 3mm), mostly falling on Thu night. Warm (max 28°C on Wed morning, min 25°C on Fri night). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Warm (max 28°C on Mon morning, min 24°C on Sat night). Wind will be generally light.

Wednesday
15
Thursday
16
Friday
17
Saturday
18
Sunday
19
Monday
20
Tuesday
21
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
1
0
0
0
0
0
1
2
0
1
1
0
1
0
0
2
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.6
SSW
10
0.5
E
10
0.8
E
9
0.9
E
8
0.9
E
8
1.1
ESE
9
1.2
ESE
9
1
ESE
9
0.9
E
8
0.9
E
9
1.2
E
9
1.2
E
9
1.2
E
9
1.2
E
9
1.1
E
10
1.2
E
9
1.2
E
10
1.3
ENE
11
1.3
ENE
11
1.4
ENE
12
1.3
ENE
11
Wave Graph
Metric surfscale
Energy kJ
61
47
102
115
116
172
199
162
116
127
240
225
240
244
216
251
296
415
400
532
415
Wind (km/h)
15
SSW
20
S
25
S
15
SSW
15
S
10
SSW
20
SSE
15
SE
10
SE
10
SE
15
SE
5
ESE
5
SSE
10
SSE
10
SW
10
SSW
20
SSW
10
SW
15
SSW
20
SSW
10
SSW
Wind State
cross-on
cross-on
cross-on
cross-on
cross-on
cross-on
on
cross-on
cross-on
on
on
cross-on
glassy
on
cross-on
cross-on
cross-on
cross
cross-on
cross-on
cross-on
High Tide
6:30PM1.49m
4:59AM1.59m
7:02PM1.48m
5:50AM1.55m
7:32PM1.46m
6:39AM1.48m
7:58PM1.44m
7:29AM1.37m
8:23PM1.43m
8:23AM1.24m
8:48PM1.41m
9:27AM1.12m
9:15PM1.38m
Low Tide
11:20AM-0.11m
11:37PM0.93m
12:03PM-0.03m
00:17AM0.85m
12:43PM0.10m
00:59AM0.78m
1:19PM0.26m
1:43AM0.71m
1:53PM0.43m
2:30AM0.67m
2:23PM0.60m
3:25AM0.63m
2:53PM0.76m
clear
clear
part cloud
part cloud
part cloud
rain showers
part cloud
part cloud
rain showers
clear
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
rain showers
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:35
4:35
4:35
4:37
4:37
4:37
4:39
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:53
6:52
6:52
6:52
6:52
6:51
6:51
 mm
2
1
3
Temp °C
28
28
26
28
28
26
27
27
25
27
27
25
27
27
25
28
28
26
28
28
26
Feels °C
31
30
28
32
31
30
29
29
28
30
28
28
29
29
28
30
29
30
31
31
30
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
Map placeholder
How to use the Wavefinder 
submit an eyeball surf report

Quick surf report for Kuminatu:

join our community of surf reporters

FREE! Surf-Forecast.com widget for your website

The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Kuminatu surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.


Information about the Kuminatu Surf forecast

The above surf forecast table for Kuminatu provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Kuminatu can be found by selecting the local surf guide option on the grey menu. Our Kuminatu 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 (Kuminatu) 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 Kuminatu 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.

Kuminatu is 6 km (4 miles) from Katsuura. If you plan a holiday in Chiba, look for hotels and other accommodation in Katsuura. Katsuura has rooms for a wide range of budgets as well as car hire and transport links.

Nearest locationNearest