Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 2 pm 27 Jul 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
27.1° 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 27 Jul 2026:

  • Best quality surf: Monday 3 Aug, 6AM (local time) - 5ft (1.6m), 15s period, SE swell with cross-offshore winds.
  • Most powerful swell: Monday 3 Aug, 9PM (local time) - 7ft (2.2m), 16s period, SE swell with 2,537 kJ wave energy.
  • Next surfable swell (1★+): Tuesday 28 Jul, 3AM (local time) - 4ft (1.2m), 7s period with NE 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 Tuesday (Jul 28) at 3AM. The primary swell is predicted to be 1.2m and 7s period with a secondary swell of 1.0m and 7s. Another secondary swell of 0.6m and 10s is also forecast. 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 2.2m 16s and forecast to arrive on Monday (Aug 03) at 9PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 4s period and expected on Saturday (Aug 01) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Tue 28th Jul)4ft (1.2m) 7s
Best Surf 6AM (Mon 3rd Aug)5ft (1.6m) 15s
Most Powerful 9PM (Mon 3rd Aug)7ft (2.2m) 16s

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


The Lowdown

Alright folks, Rusty here. Let’s have a look at what’s on the cards for Onjuku over the next couple of weeks.

To be straight with you, the first week is a bit of a write-off. We’ve got a dry spell from the 27th of July all the way through to the 1st of August. Nothing worth paddling out for. The swell is tiny, the wind is messy, and the energy is just not there. You’re better off saving your wax.

Things finally start to look up on the morning of Sunday, the 2nd of August. We get a glassy morning with a glassy wind from the NNE at 3 mph. The swell comes in at 3 ft from the SE, with a very long period of 16 seconds. The combined energy is moderate, sitting at (544). This is a proper groundswell with a lot of push, and you’ll find longer gaps between sets. The water temp is 81°, which is about a degree warmer than usual for this time of year, so it’s comfortably warm.

Now, the standout is Monday the 3rd of August. No question. The morning delivers a clean 6 ft swell from the SE, with a very long period of 16 seconds and a combined energy of (1470). The wind is a light offshore from the ENE at 6 mph, keeping the surface clean. This is where the experienced surfers are going to get their fix. The 6 ft afternoon is a bit more cross-choppy, but the morning is the pick.

The real heavy stuff shows up on Tuesday the 4th of August morning. We’re looking at 10 ft from the SE with an 18-second period and a combined energy of (5673). That’s very strong energy. The wind is cross-off from the NE at 9 mph, keeping it clean. But I’ve got to be honest with you – at 10 ft, this is getting into expert-only territory. For the average surfer, this is going to be a handful. The afternoon gets even bigger at 12 ft, and the wind shifts to a cross-shore, so that’s more for the big-wave crew.

From Wednesday the 5th of August onward, the swell just keeps pumping. 13 ft, 16 ft, 20 ft, 21 ft… it’s a proper ocean. The wind stays cross-off for most of it, keeping the face clean, but the size is too big for this break. The reports say it’s too big for Onjuku, so unless you’re on a gun and know what you’re doing, give it a miss. The combined energy goes through the roof, hitting (26349) on the 7th of August morning. That’s massive.

By the weekend of the 9th and 10th of August, the wind turns nasty. Gale force cross-onshore and onshore winds, with rain and thunderstorms. The swell is still big, but it’s a complete mess. Not worth it.

So, the best bet in the whole window is Monday the 3rd of August morning. Clean, 6 ft, long-period SE groundswell, light offshore wind. It’s the one to circle on the calendar. The 2nd of August morning is also a good warm-up with glassy conditions.

Rusty.

Short Range Forecast

Light rain (total 8mm), mostly falling on Wed night. Warm (max 29°C on Wed morning, min 23°C on Mon afternoon). Mainly fresh winds.

Days 5-7 Weather Summary

Light rain (total 2mm), mostly falling on Fri morning. Warm (max 28°C on Sun morning, min 24°C on Fri night). Wind will be generally light.

Mon
27
Tuesday
28
Wednesday
29
Thursday
30
Friday
31
Saturday
1
Sunday
2
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
1
1
0
0
1
0
0
1
0
0
0
0
0
0
1
1
3
2
3
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
NE
7
1.3
NE
7
0.9
ENE
8
0.8
ENE
8
0.6
ENE
7
0.8
SSW
6
0.7
SSW
7
0.8
NE
6
0.6
ENE
7
0.7
ENE
8
0.6
ENE
7
0.4
SE
9
0.4
ENE
7
0.4
SE
10
0.5
NE
7
0.5
ESE
10
0.5
ESE
10
1
SE
16
1.1
SE
14
1.4
SE
15
Wave Graph
Metric surfscale
Energy kJ
124
162
102
79
41
48
48
49
35
52
37
31
21
36
25
55
57
489
466
844
Wind (km/h)
25
NE
15
NNE
15
E
15
SSE
30
WSW
5
NNE
10
E
20
NE
15
ENE
5
SE
10
S
15
S
10
E
20
NE
15
NE
15
ENE
5
ENE
5
ENE
10
SE
0
ESE
Wind State
cross-off
cross-off
cross-off
on
cross-on
glassy
cross
cross-off
cross-off
cross-on
on
on
cross
cross-off
cross-off
cross-off
cross-off
glassy
cross-on
glassy
High Tide
5:00PM1.23m
2:32AM1.33m
5:21PM1.27m
3:19AM1.38m
5:42PM1.30m
4:01AM1.42m
6:03PM1.32m
4:41AM1.43m
6:23PM1.34m
5:20AM1.41m
6:44PM1.36m
6:00AM1.37m
7:05PM1.38m
Low Tide
9:28PM1.02m
10:04AM0.17m
10:04PM0.97m
10:37AM0.13m
10:38PM0.90m
11:08AM0.12m
11:11PM0.83m
11:38AM0.14m
11:45PM0.75m
12:06PM0.20m
00:21AM0.68m
12:33PM0.28m
00:59AM0.61m
part cloud
part cloud
part cloud
part cloud
thunderstorm
clear
clear
thunderstorm
part cloud
part cloud
part cloud
light rain
thunderstorm
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
clear
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:43
4:43
4:45
4:46
4:46
4:47
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:45
6:45
6:45
6:44
6:43
6:42
6:40
 mm
1
7
1
1
Temp °C
24
23
26
27
27
29
28
24
26
26
26
27
27
25
27
27
25
28
28
26
Feels °C
23
24
29
29
26
33
32
26
29
30
29
32
31
27
29
30
28
31
31
30
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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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