Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 am 31 Jul 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
26.8° C
0.5° 

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


Onjuku surf forecast from 31 Jul 2026:

  • Best quality surf: Tuesday 4 Aug, 9AM (local time) - 11ft (3.5m), 16s period, SE swell with cross-offshore winds.
  • Most powerful swell: Thursday 6 Aug, 6AM (local time) - 15ft (4.5m), 17s period, SSE swell with 10,762 kJ wave energy.
  • Next surfable swell (1★+): Saturday 1 Aug, 12AM (local time) - 1.5ft (0.4m), 9s period with SE 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 (Aug 01) at 12AM. The primary swell is predicted to be 0.4m and 9s period with a secondary swell of 0.6m and 6s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 4.5m 17s and forecast to arrive on Thursday (Aug 06) at 6AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 5s period and expected on Monday (Aug 03) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+)12AM (Sat 1st Aug)1.5ft (0.4m) 9s
Best Surf 9AM (Tue 4th Aug)11ft (3.5m) 16s
Most Powerful 6AM (Thu 6th Aug)15ft (4.5m) 17s

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


The Lowdown

G’day, Rusty here, lookin’ at the Onjuku forecast for the next couple of weeks. The water’s sittin’ at a warm 80°, which is pretty much spot on for this time of year, so no surprises there.

The first few days are pretty quiet. Friday the 31st has a tiny 2ft swell from the SSW, with a short 6-second period and weak energy (84). It’s surfable, but very ordinary. Saturday the 1st drops off even more with a 1ft SE swell, though the morning is glassy – that’s a lovely look, but the size just isn’t there. Then on Sunday the 2nd, we finally get a pulse. A 4ft SE groundswell (16 sec) rolls in, with the combined energy jumping to 622 (moderate), and a clean cross-off wind from the ENE. That’s the standout for the first week. The swell builds through the day to 4ft, still clean, but the wind picks up to 15 mph, making it a bit lumpy. That Sunday morning window is the one to target – it’s not huge, but the conditions are right.

Monday the 3rd pushes into bigger territory with a 7ft SE swell and a long 16-second period, energy ripping at 2404 (strong). The wind is cross-off but at 15 mph, so it’s clean but chunky. By Tuesday the 4th, the swell hits 12ft, and the energy is massive (6680, very strong). That’s too big for this break – it’s only for experts. The whole week from the 4th to the 7th is pumping with 12ft to 15ft swell, but it’s just too much for Onjuku. The wind turns cross-shore and onshore, making it messy. If you’re a kite surfer, the 4th and 5th look interesting, but for paddle surfing, it’s a pass.

After the big stuff, Sunday the 9th rolls in with a 5ft ESE swell and a 13-second period, energy 1095 (moderate). The morning is clean with a cross-off breeze from the ENE at 9 mph. That’s the best call for the second week – solid, clean, and manageable. The following days, Monday the 10th through to the 14th, hold around 5ft to 6ft, but the wind gets strong, especially on the 11th and 12th with 25 mph offshore winds. That’s clean but a real fight to paddle into. Then Saturday the 15th, the energy drops to 501 (weak), with a 4ft E swell and a light cross-off – it’s surfable, but nothing special.

There are a few gaps: from Friday the 31st to Saturday the 1st, there’s really nothing worth paddling out for. And from the 4th to the 8th, it’s either too big or too messy. The standout sessions are Sunday the 2nd morning and Sunday the 9th morning. The 9th is the best of the lot overall – clean, moderate swell, and a long period that’ll give some nice lines at Onjuku, especially since it’s a beach break and that long period can make it a bit straight, but with the cross-off, it should be fine. Crowds are possible here, so get in early.

Rusty.

Short Range Forecast

Mostly dry. Warm (max 29°C on Fri morning, min 23°C on Sun night). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Warm (max 26°C on Tue morning, min 23°C on Tue night). Wind will be generally light.

Friday
31
Saturday
1
Sunday
2
Monday
3
Tuesday
4
Wednesday
5
Thursday
6
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
0
1
1
0
2
3
1
3
3
3
4
!
!
!
!
!
!
!
!
4
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.7
SSW
6
0.7
S
6
0.4
SE
9
0.4
SE
11
0.4
SE
16
0.5
SE
18
1.1
SE
16
1.3
SE
15
1.5
SE
15
2.1
SE
16
2.5
SE
18
3
SE
16
3.5
SE
16
3.5
SE
16
3.5
SE
16
3.5
SSE
16
4
SSE
16
4
SSE
17
4.5
SSE
17
4
SSE
16
3
S
15
Wave Graph
Metric surfscale
Energy kJ
41
41
31
29
93
152
560
714
949
2247
4257
4062
6355
6021
6591
6747
8098
9591
10731
8653
4774
Wind (km/h)
10
NNE
10
SE
5
SE
5
SSW
15
S
5
SSW
10
ENE
25
ENE
25
NNE
25
NNE
25
NE
15
NE
25
NE
25
NE
25
NNE
25
NE
20
ENE
10
ENE
15
E
15
E
10
ESE
Wind State
cross-off
cross-on
glassy
glassy
on
glassy
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross
cross
cross
High Tide
6:23PM1.34m
5:20AM1.41m
6:44PM1.36m
6:00AM1.37m
7:05PM1.38m
6:43AM1.30m
7:27PM1.38m
7:32AM1.21m
7:51PM1.38m
8:31AM1.11m
8:17PM1.37m
9:58AM1.02m
8:49PM1.35m
Low Tide
11:38AM0.14m
11:45PM0.75m
12:06PM0.20m
00:21AM0.68m
12:33PM0.28m
00:59AM0.61m
1:00PM0.40m
1:40AM0.55m
1:27PM0.54m
2:28AM0.50m
1:55PM0.69m
3:27AM0.45m
2:20PM0.85m
part cloud
part cloud
part cloud
clear
clear
clear
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
clear
part cloud
part cloud
clear
part cloud
clear
clear
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:46
4:46
4:47
4:48
4:48
4:48
4:50
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:43
6:42
6:40
6:39
6:38
6:38
6:37
 mm
1
Temp °C
29
28
27
29
29
27
29
26
24
25
25
24
26
26
24
26
26
26
28
28
26
Feels °C
33
31
31
33
33
31
33
27
24
26
25
25
25
26
24
27
27
30
30
31
30
  • Map Icons:
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  • 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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