Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 am 26 Aug 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
27.9°C
1.1° 

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


Onjuku surf forecast from 26 Aug 2026:

  • Best quality surf: Thursday 27 Aug, 6PM (local time) - 2.5ft (0.7m), 13s period, E swell with offshore winds.
  • Most powerful swell: Wednesday 2 Sep, 12PM (local time) - 4.5ft (1.3m), 16s period, SSW swell with 839 kJ wave energy.
  • Next surfable swell (1★+): Thursday 27 Aug, 6PM (local time) - 2.5ft (0.7m), 13s 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 Thursday (Aug 27) at 6PM. The primary swell is predicted to be 0.7m and 13s period with a secondary swell of 0.8m and 10s. The wind is predicted to be offshore as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 1.3m 16s and forecast to arrive on Wednesday (Sep 02) 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 1.0m 5s period and expected on Sunday (Aug 30) at 9PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 6PM (Thu 27th Aug)2.5ft (0.7m) 13s
Best Surf 6PM (Thu 27th Aug)2.5ft (0.7m) 13s
Most Powerful12PM (Wed 2nd Sep)4.5ft (1.3m) 16s

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


The Lowdown

Alright, grab a coffee, let's have a look at what's going on for Onjuku.

Honestly mate, the next week and a half is a bit of a write-off. We’ve got a real slow patch here from now through the end of August and into the first few days of September. There are reports of swell, but the wind is all over the shop, mostly cross-onshore, and that's just messing up the surface on what would otherwise be a fun little wave. The energy is there, but the quality isn't. Most of that time, we're looking at poor surf conditions with the odd marginal session if you’re desperate for a paddle. The water is sitting at about 82°F right now, which feels a touch warmer than normal for this time of year, so at least the wait won't be chilly.

Things start to get a bit more interesting towards the back half of the first week of September. There’s a pulse of very long period groundswell from the SSW arriving around Wednesday the 2nd. We’re talking 4ft to 4ft with a period of 15 seconds, and the combined energy is going to be strong at around 1200. It’s a fair bit of juice, but with winds directly onshore and a beach break setup, it’s going to be a messy, blown-out mess. This kind of long period groundswell needs a point or reef to shine. Honestly, with that wind and power, the setup looks more interesting for kite surfing than a clean paddle session.

The real standout, and the only one I’d circle on the calendar, is Wednesday the 9th of September. After all that junk, we get clean, offshore winds from the north. The swell drops back to a very manageable 5ft from the south with a decent 11-second period. The combined energy is moderate (542), but it's that light offshore wind that makes the difference. Expect some clean, lined-up sets, and given Onjuku is inconsistent, it's a real treat when the stars align. If you can only pick one day in the next two weeks, that's your morning session right there. Keep in mind it’s a high-quality window, not a huge swell, but clean and workable. Crowds are sometimes a thing here, so get in early.

Late on Saturday the 5th, there is a brief window of glassy conditions with a 5ft ENE windswell, but it’s not the strongest and the quality is only rated as good, not great. It's an option for the die-hards but Wednesday the 9th is where the real fun is.

Rusty

Short Range Forecast

Moderate rain (total 19mm), heaviest on Thu morning. Warm (max 30°C on Wed morning, min 23°C on Thu afternoon). Wind will be generally light.

Days 4-6 Weather Summary

Light rain (total 4mm), mostly falling on Sun afternoon. Warm (max 26°C on Sat morning, min 24°C on Sun night). Wind will be generally light.

Wednesday
26
Thursday
27
Friday
28
Saturday
29
Sunday
30
Monday
31
Tuesday
1
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
1
0
0
0
1
0
0
1
0
0
1
0
1
1
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)
1.2
S
10
0.9
SSE
9
0.9
SSE
9
0.8
SSE
10
0.7
E
13
0.7
E
13
0.7
E
12
0.7
E
12
0.6
E
12
0.6
E
12
0.5
E
11
0.5
E
11
0.5
E
11
0.5
E
11
0.5
E
11
0.9
NE
7
0.9
NE
7
0.9
ENE
7
1
E
8
0.9
ENE
8
0.8
SSW
14
Wave Graph
Metric surfscale
Energy kJ
257
146
121
120
173
163
148
139
99
96
63
61
58
59
57
79
91
94
127
100
269
Wind (km/h)
15
WSW
25
SW
25
SW
25
SW
20
NNE
15
SW
25
SW
20
WSW
10
NNW
25
ENE
25
ENE
10
NE
10
ESE
5
E
15
NE
20
NNE
15
NE
10
NE
10
ESE
15
SSE
20
S
Wind State
cross-on
cross-on
cross-on
cross-on
cross-off
cross-on
cross-on
cross-on
cross-off
cross-off
cross-off
cross-off
cross-on
cross
cross-off
cross-off
cross-off
cross-off
cross
cross-on
on
High Tide
4:41PM1.29m
3:17AM1.37m
4:57PM1.33m
3:58AM1.42m
5:14PM1.37m
4:38AM1.44m
5:32PM1.40m
5:17AM1.43m
5:51PM1.42m
5:58AM1.39m
6:10PM1.43m
6:41AM1.32m
6:31PM1.44m
Low Tide
9:42AM0.22m
9:51PM0.85m
10:12AM0.19m
10:21PM0.74m
10:41AM0.20m
10:51PM0.63m
11:09AM0.24m
11:22PM0.53m
11:35AM0.32m
11:54PM0.43m
12:02PM0.43m
00:30AM0.36m
12:27PM0.56m
1:09AM0.32m
clear
clear
rain showers
thunderstorm
light rain
light rain
thunderstorm
thunderstorm
part cloud
part cloud
part cloud
part cloud
cloud
light rain
light rain
cloud
part cloud
part cloud
part cloud
part cloud
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:05
5:05
5:07
5:07
5:07
5:09
5:09
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:14
6:13
6:12
6:09
6:08
6:07
6:06
 mm
1
7
4
5
1
1
1
3
3
Temp °C
30
29
27
28
24
25
28
27
26
26
26
25
26
26
25
24
26
24
28
28
27
Feels °C
32
30
28
29
25
27
30
29
28
25
25
26
29
30
28
26
28
26
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)
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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.

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