Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 am 06 Aug 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
25.6° C
0.9° 

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


Onjuku surf forecast from 6 Aug 2026:

  • Best quality surf: Sunday 9 Aug, 3AM (local time) - 5.5ft (1.7m), 13s period, ESE swell with glassy winds.
  • Most powerful swell: Thursday 6 Aug, 6PM (local time) - 8ft (2.4m), 13s period, SSE swell with 1,780 kJ wave energy.
  • Next surfable swell (1★+): Saturday 8 Aug, 3AM (local time) - 4.5ft (1.3m), 11s period with S 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 08) at 3AM. The primary swell is predicted to be 1.3m and 11s period with a secondary swell of 1.3m and 9s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 2.4m 13s and forecast to arrive on Thursday (Aug 06) at 6PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 3s period and expected on Monday (Aug 10) at 12PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Sat 8th Aug)4.5ft (1.3m) 11s
Best Surf 3AM (Sun 9th Aug)5.5ft (1.7m) 13s
Most Powerful 6PM (Thu 6th Aug)8ft (2.4m) 13s

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


The Lowdown

Alright, this is Rusty here, checking in on the local surf scene for the next couple of weeks.

Alright, so we’ve got a bit of a mixed bag on the way. The first decent surf rolls in on Thursday morning, the 6th, and it’s a solid one if you’ve got the skills. The sea is pumping with a strong 7ft SSE swell, and the combined energy is a hefty 1955, so there’s some serious power in the water. The water’s sitting at 78°, which is pretty much what you’d expect for this time of year. The wind is a clean cross-offshore from the ENE, and the period is a meaty 13 seconds, so the waves are going to have some real shape to them. This is an exposed spot, so it’s getting all that energy. The catch is, this is about as good as it gets for the whole run, but with that size, it’s strictly for the experienced crew. Beginners, stay on the beach for this one. It’s also inconsistent here, so don’t expect a wave every minute, but when they come, they’ll be worth it.

Thursday afternoon, the wind swings to a cross-on from the ESE, and the quality drops off with the chop. Don’t get excited about that session.

Friday the 7th is a write-off. We’ve got a risk of thunderstorms and a cross-on wind that’s going to make a mess of the 6ft S swell. Not worth paddling out.

Saturday the 8th drops off further. The swell is down to 4ft in the morning and the wind is light cross-on. The energy is weak at 604, so it’s a small, choppy day.

Now, Sunday the 9th looks like the real standout. The swell is 6ft from the ESE, and the wind is a light cross-offshore from the ENE. That’s the magic combo. The period is a nice 13 seconds, so the lines will be clean. The energy is strong at 1188. This is the best session for the intermediate surfer, with much cleaner, more manageable waves than Thursday. This is the one to circle on the calendar. It’s still inconsistent, so be patient, but the quality will be there.

Monday the 10th picks up a fresh 19 mph NE wind. The swell is 5ft from the E. The wind is cross-off, so it’s clean, but that wind strength is going to make it a battle. The energy is low at 759. It’s a tough paddle for not much reward.

Tuesday the 11th has a great morning window. The swell is 6ft from the ENE and the wind is a clean offshore from the N. The period is 11 seconds, and the energy is strong at 1363. This is another one for the experienced crew, as it’s a powerful wave. The afternoon is a bust with a strong breeze from the NNE.

From Wednesday the 12th onwards, the overall trend is a slow decline. The swell holds around 5ft to 6ft for a few days, but it’s mostly from the E or NE. The wind is consistently cross-offshore, which is a positive, keeping the faces clean. The energy drops into the three-digit range, and the periods settle around 8 to 11 seconds. The quality is marginal, with the best chance being a ‘very good’ call on Friday morning the 14th, with a 5ft E swell and light cross-off wind. But it’s not a patch on the first week.

The second week from the 16th onwards is the real slump. The swell drops to 3ft to 5ft, and the energy is weak, often below 400. The wind stays cross-off, keeping it clean, but the waves are just too small and weak to get excited about. The period drops to 8-10 seconds, so it’s short-period windswell. There’s no real punch. The 19th is a flat-out ‘poor’ call, and it just fades out from there.

To sum it up: Thursday morning the 6th is the big, powerful day for the experts. Sunday the 9th is the best all-rounder for the intermediate surfer, with clean, fun waves. The rest is a slow fade into small, clean but weak conditions. Get your sessions in early.

Rusty.

Short Range Forecast

Light rain (total 3mm), mostly falling on Thu night. Warm (max 28°C on Thu morning, min 24°C on Sat night). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Warm (max 29°C on Tue morning, min 22°C on Mon night). Winds increasing (light winds from the ENE on Sun morning, fresh winds from the NNE by Tue afternoon).

Thursday
6
Friday
7
Saturday
8
Sunday
9
Monday
10
Tuesday
11
Wednesday
12
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
4
2
2
2
1
1
2
2
3
4
3
3
1
1
1
4
0
2
2
2
4
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
2.2
SSE
13
2.2
SSE
12
2.1
S
13
1.8
S
12
1.6
S
12
1.4
S
11
1.2
S
11
1.3
ESE
13
1.6
ESE
13
1.7
ESE
13
1.7
ESE
13
1.6
ESE
12
1.5
E
12
1.5
E
11
1.5
E
11
1.8
ENE
11
1.5
E
10
1.6
ENE
9
1.5
NE
8
1.5
ENE
9
2.1
E
12
Wave Graph
Metric surfscale
Energy kJ
1572
1405
1537
957
702
457
332
624
799
1013
931
781
617
543
546
692
459
383
268
344
1269
Wind (km/h)
15
ENE
15
ESE
10
SE
15
SSE
15
SSE
10
SSE
10
SE
15
SSE
5
S
10
ENE
15
E
15
NNE
30
NE
30
NE
30
NNE
25
N
40
NNE
30
NNE
20
NE
20
ENE
10
N
Wind State
cross-off
cross-on
cross-on
cross-on
on
on
cross-on
cross-on
on
cross-off
cross
cross-off
cross-off
cross-off
cross-off
off
cross-off
off
cross-off
cross-off
off
High Tide
9:58AM1.02m
8:49PM1.35m
12:56PM1.00m
9:31PM1.33m
10:43PM1.31m
4:10PM1.23m
00:23AM1.32m
4:33PM1.30m
1:48AM1.37m
4:57PM1.35m
2:54AM1.44m
5:21PM1.37m
Low Tide
2:20PM0.85m
4:43AM0.41m
2:29PM1.00m
6:13AM0.33m
7:36AM0.23m
7:43PM1.16m
8:40AM0.12m
8:57PM1.09m
9:31AM0.04m
9:44PM0.99m
10:15AM0.00m
10:23PM0.88m
clear
clear
thunderstorm
thunderstorm
clear
clear
clear
clear
clear
clear
clear
part cloud
part cloud
clear
clear
clear
part cloud
part cloud
part cloud
clear
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:50
4:50
4:52
4:52
4:52
4:54
4:54
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:37
6:37
6:36
6:35
6:32
6:31
6:30
 mm
1
2
Temp °C
28
28
26
28
28
25
27
27
25
27
27
24
26
25
23
29
25
24
26
26
25
Feels °C
31
31
30
31
31
28
30
29
28
28
28
26
24
23
21
27
22
23
26
26
27
  • 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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