Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 2 am 28 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: Tuesday 4 Aug, 6AM (local time) - 11ft (3.5m), 18s period, SE swell with offshore winds.
  • Most powerful swell: Tuesday 4 Aug, 9AM (local time) - 11ft (3.5m), 18s period, SE swell with 8,107 kJ wave energy.
  • Next surfable swell (1★+): Tuesday 28 Jul, 6AM (local time) - 3.5ft (1.0m), 8s period with ENE 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 6AM. The primary swell is predicted to be 1.0m and 8s period with a secondary swell of 0.5m and 10s. 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 3.5m 18s and forecast to arrive on Tuesday (Aug 04) 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 1.4m 6s period and expected on Tuesday (Aug 04) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 6AM (Tue 28th Jul)3.5ft (1.0m) 8s
Best Surf 6AM (Tue 4th Aug)11ft (3.5m) 18s
Most Powerful 9AM (Tue 4th Aug)11ft (3.5m) 18s

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


The Lowdown

Alright, I’m looking at the forecast for Onjuku here, and I gotta be straight with you – the first week is a bit of a struggle. The surf is small and the conditions are just ordinary. We’ve got a run of days from July 28th right through August 1st where the swell is tiny, mostly under 3 feet, and the wind is all over the place. The morning of the 29th is a standout early on, with a glassy, clean 3ft SSW swell, but the waves are weak and inconsistent. The energy is low (113), so it’s a bit of a pokey wave for a longboard or a foamie. The water temp is about average for the time of year.

Then the real action starts to build. From August 2nd, the swell starts to pick up, and by August 4th, we’re looking at a serious pulse of long-period groundswell from the SE. The morning of the 4th is the best on offer. The swell is 10ft, with a period of 18 seconds, and the wind is a clean cross-offshore from the NE. The energy is massive (6061), and the waves should be powerful and lined up. This is a standout session for experienced surfers, but it’s going to be well overhead. This is not a beginner wave. August 5th is even bigger, with 18ft swell, but that’s getting into serious territory – only for the experts. The wind stays favorable, but the swell is too big for the average punter.

August 6th is still huge, but the wind shifts to a cross-shore and then a cross-onshore, making it messy. The quality drops off fast after that. From August 7th to the 8th, the swell is still big, but the wind is onshore and choppy, so it’s a write-off. You’ll see some cleanup on the 9th and 10th of August, with the swell dropping back to a more manageable 4ft to 5ft, but the wind is still cross or cross-off, so it’s not perfect. The morning of August 11th has a clean 4ft swell from the ESE with a period of 11 seconds, and the energy is moderate (455). It’s a better option, but it’s not the same as that big clean pulse we saw earlier.

So, to sum it up: the first week is a flat, slow grind. The real standout is the morning of August 4th, with that big, clean, long-period swell. The morning of August 11th is a decent second option for a smaller, cleaner session. The second week is a bit of a mixed bag with some decent swell, but the wind is always a factor.

Rusty

Short Range Forecast

Light rain (total 5mm), mostly falling on Tue night. Warm (max 28°C on Wed morning, min 24°C on Wed night). Wind will be generally light.

Days 4-6 Weather Summary

Light rain (total 4mm), mostly falling on Fri night. Warm (max 29°C on Fri morning, min 24°C on Fri night). Wind will be generally light.

Tuesday
28
Wednesday
29
Thursday
30
Friday
31
Saturday
1
Sunday
2
Monday
3
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
2
1
1
0
0
1
1
0
1
0
0
1
1
1
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)
0.9
ENE
8
0.7
ENE
8
0.6
ENE
8
1.6
SW
7
1.4
SW
7
0.8
SSW
7
0.6
SSW
7
0.4
SE
9
0.4
SE
9
0.4
SE
9
0.4
ENE
8
0.4
SE
9
0.4
SE
15
0.4
SE
14
0.6
SE
14
1
SE
14
1.1
SE
15
1.6
SE
15
2.1
SE
16
2.4
SE
16
3
SE
17
Wave Graph
Metric surfscale
Energy kJ
81
58
45
244
200
59
42
31
22
30
22
31
58
71
164
373
535
1135
2415
3048
4935
Wind (km/h)
10
ENE
15
SSW
20
WSW
5
S
10
SSW
15
N
5
ESE
15
S
0
SSW
10
NNE
15
ESE
15
NE
15
ENE
15
ESE
10
ESE
5
ESE
10
SE
10
E
15
ENE
20
ENE
20
NNE
Wind State
cross-off
on
cross
glassy
cross-on
off
cross
on
glassy
off
cross
cross-off
cross-off
cross
cross-on
cross-on
cross-on
cross
cross-off
cross-off
cross-off
High Tide
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
6:43AM1.30m
7:27PM1.38m
Low Tide
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
1:00PM0.40m
1:40AM0.55m
part cloud
part cloud
thunderstorm
clear
thunderstorm
thunderstorm
part cloud
part cloud
clear
part cloud
part cloud
thunderstorm
light rain
part cloud
cloud
part cloud
part cloud
part cloud
part cloud
clear
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
4:48
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:45
6:45
6:44
6:43
6:42
6:40
6:39
 mm
2
1
2
3
1
Temp °C
26
27
27
28
28
26
28
28
26
29
28
26
25
26
25
27
26
25
26
26
24
Feels °C
29
29
28
32
31
30
31
31
30
32
31
29
27
28
28
30
28
27
26
26
25
  • 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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