Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 2 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 30 Jul 2026:

  • Best quality surf: Tuesday 4 Aug, 12AM (local time) - 11ft (3.5m), 18s period, SE swell with cross-offshore winds.
  • Most powerful swell: Wednesday 5 Aug, 9AM (local time) - 15ft (4.5m), 16s period, SSE swell with 10,257 kJ wave energy.
  • Next surfable swell (1★+): Friday 31 Jul, 9AM (local time) - 2.5ft (0.7m), 6s period with SSW 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 Friday (Jul 31) at 9AM. The primary swell is predicted to be 0.7m and 6s period with a secondary swell of 0.4m and 9s. The wind is predicted to be cross-offshore as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 4.5m 16s and forecast to arrive on Wednesday (Aug 05) at 9AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 6s period and expected on Monday (Aug 03) at 6AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 9AM (Fri 31st Jul)2.5ft (0.7m) 6s
Best Surf12AM (Tue 4th Aug)11ft (3.5m) 18s
Most Powerful 9AM (Wed 5th Aug)15ft (4.5m) 16s

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


The Lowdown

Alright folks, Rusty here. Let’s talk about what’s on offer for the next couple of weeks.

We’ve got a bit of a slow start, but the first real surf worth paddling out for hits Onjuku on Sunday, August 2nd. The whole week leading up to that is pretty flat and uninspiring, with tiny swells and very ordinary conditions. Friday the 31st and Saturday the 1st are barely worth a look, so save your energy.

Sunday morning, August 2nd, is where it gets interesting. The swell picks up to 4 ft from the SE, with a solid 16-second period, and the wind is light cross-offshore from the ENE. That’s going to give you clean, lined-up waves with some real push. The combined energy is moderate (690). It’s a bit inconsistent here, but when the sets roll through, they’ll be worth the wait. This is the standout of the early window.

Monday, August 3rd, the swell jumps to 7 ft then 8 ft in the afternoon, still from the SE with a very long 17-18 second period. The wind stays cross-off, so the surf will be clean, but it’s getting serious. That long period groundswell can make the waves wall up and close out a bit at a beach break like Onjuku, so it’ll be more of a challenge. The combined energy is strong (2610-3911). This is more for the experienced crew.

Then from Tuesday, August 4th, through to Thursday, August 6th, we get a monster pulse. The swell hits 13 ft to 15 ft from the SSE with a 16-17 second period. The combined energy is off the charts (8706 to 10319). The wind is still cross-off, but honestly, this is too big for Onjuku. It’s going to be a washing machine, and only absolute experts should even think about it. This is more kite-surfing territory than paddle surfing.

The surf drops back down on Friday, August 7th, to 6 ft, but the wind turns cross-on from the SE, which will chop it up. The conditions are marginal through the weekend and into the next week.

Looking further out, Thursday, August 13th, is the next standout. The morning session is looking glassy with a light S wind, and a 5 ft swell from the E with a 13-second period. The combined energy is moderate (1139), and the offshore glassy conditions mean it’ll be clean and solid. The swell direction is a bit off the optimum, but for a clean, fun-size wave, this is the best call in the second week. The afternoon goes onshore and messy, so get it early.

Overall, the pick of the whole 16-day window is the Sunday morning, August 2nd. The swell is a nice size, the period is good, and the wind is clean. For the more experienced, the Monday and Tuesday morning of that same week offer a bigger, more powerful challenge, but it’s not for the faint-hearted.

Stay stoked, and keep an eye on the sky.

Rusty

Short Range Forecast

Mostly dry. Warm (max 29°C on Fri morning, min 24°C on Sun night). Wind will be generally light.

Days 4-6 Weather Summary

Light rain (total 2mm), mostly falling on Wed night. Warm (max 27°C on Wed morning, min 23°C on Mon night). Winds decreasing (fresh winds from the NE on Tue morning, light winds from the E by Wed night).

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
0
1
0
1
3
2
3
2
3
!
!
!
!
!
!
!
!
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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
1.4
SE
15
2.1
SE
17
2.5
SE
18
3.5
SE
18
4
SE
17
4
SE
17
4
SE
16
4.5
SSE
16
4.5
SSE
16
4.5
SSE
16
4
SSE
16
3.5
S
15
2.5
S
14
Wave Graph
Metric surfscale
Energy kJ
41
41
31
29
93
152
644
714
868
2471
3681
7026
8307
8463
8326
10257
9581
9968
8037
5259
2904
Wind (km/h)
15
NNE
10
E
5
SE
0
SE
10
S
5
SW
5
ENE
25
ENE
25
NNE
25
NE
25
NE
25
NE
25
NE
25
NE
20
NE
20
NE
15
ENE
10
ESE
10
ESE
10
SE
10
SSE
Wind State
cross-off
cross
cross-on
glassy
on
cross-on
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross
cross-on
cross-on
cross-on
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
part cloud
part cloud
part cloud
clear
part cloud
part cloud
part cloud
part cloud
clear
clear
clear
part cloud
part cloud
clear
rain showers
clear
clear
clear
<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
2
Temp °C
29
28
27
29
29
28
29
27
24
25
26
24
26
25
24
27
27
26
29
29
26
Feels °C
33
32
32
32
32
33
33
29
24
25
26
24
25
24
25
29
30
30
33
33
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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