Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 am 09 Sep 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
27.9°C
1.5° 

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


Onjuku surf forecast from 9 Sep 2026:

  • Best quality surf: Wednesday 9 Sep, 9PM (local time) - 6ft (1.9m), 9s period, S swell with cross-offshore winds.
  • Most powerful swell: Wednesday 9 Sep, 6PM (local time) - 10ft (3.0m), 9s period, SSW swell with 1,202 kJ wave energy.
  • Next surfable swell (1★+): Wednesday 9 Sep, 9PM (local time) - 6ft (1.9m), 9s 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 Wednesday (Sep 09) at 9PM. The primary swell is predicted to be 1.9m and 9s period with a secondary swell of 0.3m and 16s. Another secondary swell of 1.9m and 6s 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 3.0m 9s and forecast to arrive on Wednesday (Sep 09) 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 1.1m 6s period and expected on Saturday (Sep 12) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 9PM (Wed 9th Sep)6ft (1.9m) 9s
Best Surf 9PM (Wed 9th Sep)6ft (1.9m) 9s
Most Powerful 6PM (Wed 9th Sep)10ft (3.0m) 9s

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


The Lowdown

Right, grab a coffee, let’s have a look at what’s coming for Onjuku. The next 16 days are a real mixed bag, with a lot of messy, wind-affected days to sit through before a solid run of cleaner, more powerful swell arrives deep in the second week. The water’s sitting at about 82.2°, which is a touch warmer than usual for this time of year, so you can leave the thick rubber at home.

The opening days are a write-off. Wednesday the 9th serves up an ugly 8.2ft south swell, but it’s blowing 25 mph from the southwest, cross-onshore, with a risk of thunderstorms. The water’s all stirred up and the combined energy is a moderate 963. It’s a mess. Thursday the 10th drops to 5.2ft from the northeast with a cleaner cross-off wind, but the period is a short 7 seconds, so it’s weak and won’t hold shape well. The combined energy is still moderate at 452. Nothing to get excited about.

Friday the 11th is the first real glimmer. A 1.6ft east swell rolls in with a very long 14-second period, and the wind goes offshore from the north-northeast at 12 mph. The morning is surfable but ordinary, with a combined energy of 186; the afternoon cleans up nicely, scoring some decent conditions. The energy climbs to 272. It’s small, but the offshore wind will make it glassy and clean. This is a long-period groundswell, so it might wrap a bit better than the beach breaks, but it’s tiny.

The weekend into early next week is a bit of a flat spell. Saturday the 12th and Sunday the 13th hang around 2.0ft with a 13-14 second period, but the wind is cross-off, keeping it clean. The energy stays in the 270-300 range, low to moderate. The outlook is marginal, with some questionable tides. Monday the 14th through Wednesday the 16th sees a small bump in swell to 3.9-4.3ft, but the wind swings onshore from the south or southwest, making it choppy and poor. The energy gets up to the 400s, but it’s not worth paddling out for.

Thursday the 17th is a write-off until the afternoon when the wind goes fresh offshore from the north-northeast at 19 mph. The swell is 4.6ft but with a terrible 6-second period, so it’s a bumpy, windswell mess. The energy is a moderate 256.

Now, here’s the standout. The real action starts on Friday the 18th. The morning brings a 4.9ft swell from the east-northeast with a 7-second period, but the wind is a solid offshore from the north-northeast at 16 mph. The combined energy is a strong 519. The afternoon is even more interesting: a 2.0ft swell from the south-southeast with a very long 17-second period, and the energy rockets to 652. The wind stays offshore. This is a clean, powerful groundswell, and the conditions are very good. It’s not huge, but it’s quality.

Saturday the 19th and Sunday the 20th are the real gems. The swell builds to 3.9-4.6ft from the south-southeast on Saturday, with a 16-second period, and the energy is huge at 2262. The wind is a clean cross-off. Sunday the 20th is the pick of the bunch: a 6.6ft south swell with a 15-second period, the wind goes gentle offshore from the north-northeast in the afternoon, and the energy is still massive at 1862. The conditions are excellent for experienced surfers. The combined energy is very strong (over 2000), and the long period means it’ll be a proper groundswell with good shape, but it’s best suited to the points or reefs, not the beach breaks. The swell is over 5ft, so it’s pushing into intermediate territory, and the 6.6ft sets are for the experienced crew.

Monday the 21st keeps the swell going at 6.9-7.2ft from the south with a 16-second period, the energy is a massive 2572. The morning has a near-glass-off, with the wind at just 3 mph and cross-off, making for excellent surf. The afternoon gets a bit more wind, but it’s still clean. This is a big, powerful swell.

After that, it all falls apart. Tuesday the 22nd through the end of the outlook sees the wind swing onshore from the southeast and south, bringing cross-on conditions and choppy, lumpy surf. The swell drops to 4.9-7.5ft, but the wind is 16-28 mph, ruining it. The energy is still moderate to strong, but the quality is gone. The final day, Thursday the 24th, has a 6.9ft swell but it’s cross-onshore and messy.

So, the best bet is Sunday the 20th, with that 6.6ft south groundswell and gentle offshore wind. The water’s warm, the energy is huge, and the conditions are clean. That’s the one to circle on the calendar. The second-best is the Saturday the 19th, with the slightly smaller but

Short Range Forecast

Heavy rain (total 56mm), heaviest during Wed night. Warm (max 29°C on Wed morning, min 20°C on Wed night). Mainly strong winds.

Days 4-6 Weather Summary

Moderate rain (total 10mm), heaviest on Sat morning. Warm (max 27°C on Mon morning, min 22°C on Sat morning). Wind will be generally light.

Wednesday
9
Thursday
10
Friday
11
Saturday
12
Sunday
13
Monday
14
Tuesday
15
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
2
1
2
0
1
1
1
1
1
1
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
2.5
S
8
2.5
S
9
1.6
S
9
1.6
NE
7
1.6
NE
7
1.1
ENE
7
0.5
E
14
0.5
E
14
0.5
E
14
0.6
E
14
0.6
E
13
0.6
E
13
0.6
E
13
0.9
SE
9
0.9
SE
9
1.3
SE
9
1.2
SE
9
1.3
SE
9
1.2
SE
9
0.7
E
14
0.7
E
13
Wave Graph
Metric surfscale
Energy kJ
919
955
389
228
233
117
106
101
97
134
128
128
123
125
138
255
220
238
215
201
167
Wind (km/h)
40
SW
35
SW
40
NNE
30
NNE
25
NE
20
NNE
20
NNE
20
N
20
NNE
20
NE
20
NE
15
NE
20
NE
10
E
5
S
15
S
25
SSW
20
SSW
15
SSW
15
SSW
25
SW
Wind State
cross-on
cross-on
cross-off
cross-off
cross-off
off
off
off
cross-off
cross-off
cross-off
cross-off
cross-off
cross
on
on
on
on
on
cross-on
cross-on
High Tide
4:14PM1.34m
3:06AM1.40m
4:32PM1.36m
3:56AM1.45m
4:50PM1.39m
4:41AM1.47m
5:08PM1.41m
5:24AM1.44m
5:26PM1.43m
6:04AM1.38m
5:44PM1.44m
6:45AM1.29m
6:03PM1.43m
Low Tide
9:17AM0.17m
9:34PM0.80m
9:55AM0.18m
10:07PM0.64m
10:29AM0.24m
10:40PM0.50m
10:59AM0.34m
11:13PM0.38m
11:26AM0.45m
11:46PM0.30m
11:50AM0.57m
00:19AM0.26m
12:11PM0.69m
00:53AM0.27m
thunderstorm
thunderstorm
heavy rain
light rain
mod rain
mod rain
light rain
light rain
mod rain
light rain
light rain
cloud
rain showers
thunderstorm
thunderstorm
clear
part cloud
part cloud
thunderstorm
thunderstorm
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:16
5:16
5:16
5:18
5:18
5:18
5:20
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
5:54
5:53
5:52
5:51
5:49
5:47
5:46
 mm
3
3
20
3
6
9
2
3
7
3
2
1
1
3
2
2
2
Temp °C
29
28
23
21
21
21
21
20
21
23
23
24
25
26
26
27
27
26
26
26
26
Feels °C
28
27
25
19
19
20
22
20
21
24
23
26
27
29
30
29
28
28
28
27
27
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
Map placeholder
How to use the Wavefinder 
submit an eyeball surf report

Quick surf report for Onjuku:

join our community of surf reporters

FREE! Surf-Forecast.com widget for your website

The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Onjuku surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.


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.

Nearest locationNearest