Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 am 11 Sep 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
27.3°C
1.0° 

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


Onjuku surf forecast from 11 Sep 2026:

  • Best quality surf: Friday 18 Sep, 6AM (local time) - 4.5ft (1.4m), 17s period, SE swell with offshore winds.
  • Most powerful swell: Friday 18 Sep, 3PM (local time) - 8ft (2.5m), 16s period, SE swell with 3,400 kJ wave energy.
  • Next surfable swell (1★+): Saturday 12 Sep, 12AM (local time) - 2ft (0.6m), 14s period with E swell.

Best Forecast Surf Conditions for Onjuku this week:

The surf forecast for Onjuku over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Saturday (Sep 12) at 12AM. The primary swell is predicted to be 0.6m and 14s period with a secondary swell of 0.5m and 8s. The wind is predicted to be offshore as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 2.5m 16s and forecast to arrive on Friday (Sep 18) at 3PM. 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 6s period and expected on Thursday (Sep 17) at 9PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+)12AM (Sat 12th Sep)2ft (0.6m) 14s
Best Surf 6AM (Fri 18th Sep)4.5ft (1.4m) 17s
Most Powerful 3PM (Fri 18th Sep)8ft (2.5m) 16s

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


The Lowdown

Alright, let’s get into it. This is Rusty, and I’ve got the goods for Onjuku coming up over the next couple of weeks.

Right now, we’re in a bit of a flat spell, no real surf to speak of for the first few days, so don’t rush down. The water is sitting at 81°, which is a full degree warmer than usual for this time of year – feels like a bath out there, so a springy will do you fine.

Come Saturday morning, September 12, things start to show a pulse. East swell around 2ft with a clean 14-second period and a moderate offshore breeze from the north. The combined energy is still moderate at 202, but it’ll be clean and offshore, and after the previous drizzly rubbish, that’s a win. It’s not a standout, but it’s a good sign.

Sunday morning, September 13, is the first real highlight of this run. Onjuku gets 2ft from the ESE at 13 seconds, light offshore from the NNE. The energy is still moderate at 220, but the wind is gentle and offshore, so the waves will be clean and feel a bit more lined up. This is the first morning worth paddling out for – small but fun, quiet vibes.

Now, hold up for Wednesday afternoon, September 16. This is a sneaky one – glassy conditions, no wind at all (NNE at 3 mph), and 2ft from the east at 12 seconds. The energy is moderate at 241, but the glassy surface is rare these days. It’ll be small, but if you’re on a log, you’ll be grinning. Not a big day, but a sweet little session.

Then we jump ahead a week. Friday, September 18, the real swell kicks in. An east-northeast wind, offshore at 22 mph in the afternoon, with a 8ft groundswell from the SE at 16 seconds – that’s a very long period, so the waves will have serious push and shape. The combined energy is massive at 3684. This is serious. That size, 8ft, is pushing into expert territory, especially with that long period making it dumpy at the banks. Best for experienced surfers only.

Sunday, September 20, offers a cleaner window. Morning gives us 7ft from the south at 13 seconds, light ENE cross-off wind, and combined energy of 1944. The conditions are clean, and the swell is solid. This is one of the better-looking days for a competent crew.

The absolute standout of the entire outlook? Friday afternoon, September 25. Glassy conditions, a 10ft groundswell from the SE at 16 seconds – that’s very long period, proper deep-ocean energy – and the combined energy is a huge 4619. The wind is glassy from the WSW at just 3 mph. That’s a clean, powerful, heavy session for experts only. This is the one to circle on your calendar, but it’s far out, so keep checking back. The Saturday after that (September 26) pushes 12ft SE swell, but the wind swings cross-shore and the energy hits 5271 – it’s too big for the break, only for the nitro-burners.

In between, there are a few days with onshore wind and messy conditions, and from September 22 through 24, it’s mostly no-go, with some rain and fresh onshore breezes.

So, bottom line: if you want small clean fun, aim for the 13th or 16th. For power and size, the 18th and 20th are solid, and the 25th is the real long-range diamond – big, glassy, and heavy.

Stay patient, that run is coming.

Rusty.

Short Range Forecast

Moderate rain (total 15mm), heaviest on Fri afternoon. Warm (max 24°C on Sun morning, min 20°C on Fri afternoon). Wind will be generally light.

Days 4-6 Weather Summary

Moderate rain (total 10mm), heaviest on Tue afternoon. Warm (max 27°C on Mon morning, min 23°C on Wed night). Wind will be generally light.

Friday
11
Saturday
12
Sunday
13
Monday
14
Tuesday
15
Wednesday
16
Thursday
17
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
1
1
2
0
2
2
1
2
0
0
0
0
0
0
1
2
2
1
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)
0.5
E
14
0.5
E
14
0.6
E
14
0.6
E
14
0.6
E
13
0.7
ESE
13
0.7
ESE
13
0.7
E
13
0.8
SE
9
0.7
SE
9
1.1
SE
9
1.1
SE
9
1.1
SE
9
0.7
E
14
0.7
E
13
0.7
E
13
0.7
E
12
0.7
E
12
0.7
E
12
0.7
E
11
0.5
SE
20
Wave Graph
Metric surfscale
Energy kJ
106
101
136
134
128
184
176
168
108
81
188
199
192
196
167
165
148
138
132
116
194
Wind (km/h)
15
NE
20
NNE
15
NNE
20
N
20
NNE
15
NNE
15
NNE
10
E
0
SSE
10
SSW
20
SSW
20
SSW
15
SSW
20
SSW
15
SSW
5
SW
5
NNE
15
NE
20
NNE
25
NNE
25
N
Wind State
cross-off
off
off
off
cross-off
off
off
cross
glassy
on
on
cross-on
on
on
cross-on
cross-on
glassy
cross-off
cross-off
off
off
High Tide
4:50PM1.39m
4:41AM1.47m
5:08PM1.41m
5:24AM1.44m
5:26PM1.43m
6:04AM1.38m
5:44PM1.44m
6:45AM1.29m
6:03PM1.43m
7:26AM1.19m
6:22PM1.41m
8:14AM1.09m
6:42PM1.37m
Low Tide
10:29AM0.24m
10:40PM0.50m
10:59AM0.34m
11:13PM0.38m
11:26AM0.45m
11:46PM0.30m
11:50AM0.57m
00:19AM0.26m
12:11PM0.69m
00:53AM0.27m
12:28PM0.79m
1:31AM0.32m
12:40PM0.87m
2:15AM0.40m
light rain
mod rain
light rain
light rain
cloud
part cloud
part cloud
part cloud
part cloud
clear
part cloud
part cloud
thunderstorm
thunderstorm
thunderstorm
cloud
thunderstorm
cloud
cloud
cloud
light rain
<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
5:22
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
5:52
5:51
5:49
5:47
5:46
5:45
5:44
 mm
1
6
4
4
2
3
4
1
2
Temp °C
21
20
21
21
23
22
24
24
24
27
27
26
27
26
25
25
25
24
24
23
22
Feels °C
22
20
22
21
24
23
27
27
29
29
29
29
29
27
28
29
30
26
26
23
21
  • 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 Onjuku:

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 Onjuku 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 Onjuku Surf forecast

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

Onjuku is 3 km (2 miles) from Ohara. If you plan a holiday in Chiba, look for hotels and other accommodation in Ohara. Ohara has rooms for a wide range of budgets as well as car hire and transport links.

Nearest locationNearest