Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 pm 14 Sep 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
25.7°C
0.3° 

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


Onjuku surf forecast from 15 Sep 2026:

  • Best quality surf: Saturday 19 Sep, 3PM (local time) - 11ft (3.5m), 13s period, SE swell with cross-offshore winds.
  • Most powerful swell: Saturday 19 Sep, 3AM (local time) - 10ft (3.0m), 14s period, SE swell with 3,420 kJ wave energy.
  • Next surfable swell (1★+): Tuesday 15 Sep, 6PM (local time) - 2.5ft (0.7m), 14s period with E 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 (Sep 15) at 6PM. The primary swell is predicted to be 0.7m and 14s period with a secondary swell of 1.2m and 7s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Onjuku in the next 16 days are 3.0m 14s and forecast to arrive on Saturday (Sep 19) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 9s period and expected on Sunday (Sep 20) at 3AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 6PM (Tue 15th Sep)2.5ft (0.7m) 14s
Best Surf 3PM (Sat 19th Sep)11ft (3.5m) 13s
Most Powerful 3AM (Sat 19th Sep)10ft (3.0m) 14s

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


The Lowdown

G’day, I’m Rusty. Let’s get into it.

We’ve got a slow start here at Onjuku, with no real surf worth paddling out for over the first couple of days. Tuesday’s got a bit of energy in the water with a combined energy of 411, but it’s messy with a risk of thunderstorms and onshore wind – not worth wetting the suit. Wednesday and Thursday mornings are clean, but the swell’s barely there and the energy’s weak, so it’s a waiting game.

Come Friday the 17th, the swell starts to build. Thursday afternoon actually shows 8 ft of NE swell with offshore wind – strong breeze, but clean. The wave energy is ramping up to 713, but the period’s short at 8 seconds, so it’ll be a bit lumpy and hard to get into. Still, for the more experienced crew, it’s a chance to score some clean faces.

Now, the standout window is Saturday the 19th. Saturday morning is already big at 10 ft of SE swell, period 13 seconds, with clean cross-off wind and a combined energy of 3334. That’s moderate-to-strong energy. But Saturday afternoon – that’s the one. The swell hits 12 ft from the SE, same long period, and the wind and tide are lined up. The combined energy rockets to 3783. This is only for experts – way too big for beginners. The swell’s coming from the SSE, which is right in the sweet spot for Onjuku’s exposure. Expect powerful, long-period groundswell. It’s going to be a proper session for those who know what they’re doing.

Sunday the 20th keeps the goods coming. Morning has 10 ft SE swell, offshore wind from the north, clean conditions, and a combined energy of 2632. Afternoon drops to 8 ft but stays offshore and clean with 1854 energy. Still solid, still expert territory, but maybe a touch more manageable.

The following week settles down. Tuesday the 22nd afternoon is a sneaky highlight – 6 ft of SSW swell with glassy conditions and a combined energy of 1428. That’s clean, long-period energy at 14 seconds, and it’s a good option for intermediates if the tide plays ball. After that, Wednesday the 23rd gets ugly with a massive 18 ft SW swell and onshore wind – completely blown out, total washout. Then it fades into small, ordinary surf through the end of the month, with a few clean mornings but nothing to get excited about.

Best on offer: Saturday 19th afternoon at Onjuku – 12 ft SE swell, long 13-second period, offshore wind, and huge energy. That’s a day for the local chargers. Sunday 20th morning is a close second. Don’t sleep on Tuesday 22nd afternoon either – glassy, clean, and a proper change of pace.

- Rusty

Short Range Forecast

Heavy rain (total 44mm), heaviest during Tue afternoon. Warm (max 26°C on Mon night, min 19°C on Thu afternoon). Winds increasing (calm on Tue afternoon, strong winds from the NNE by Thu afternoon).

Days 5-7 Weather Summary

Heavy rain (total 60mm), heaviest during Sat morning. Warm (max 25°C on Sun afternoon, min 20°C on Thu night). Winds decreasing (strong winds from the NNE on Thu night, light winds from the ENE by Sat night).

Tuesday
15
Wednesday
16
Thursday
17
Friday
18
Saturday
19
Sunday
20
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
2
2
1
1
2
0
1
1
1
1
3
3
!
3
4
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)
1.1
SE
9
0.7
E
14
0.8
E
14
0.7
E
13
0.8
E
13
0.7
E
12
0.7
E
12
2
NE
7
2.3
NE
8
2.5
ENE
8
2.5
ENE
8
1.8
SE
15
3
SE
14
3
SE
13
3.5
SE
13
3
SE
12
3
SE
13
2.5
SE
12
2.4
SE
12
Wave Graph
Metric surfscale
Energy kJ
199
201
261
167
215
148
138
379
665
869
953
1417
3326
2795
3393
2733
2617
1769
1711
Wind (km/h)
25
SW
20
SSW
10
SW
15
NNE
20
NNE
20
NNE
25
N
40
NNE
40
NNE
40
NNE
40
NNE
40
NNE
40
NNE
30
NE
20
ENE
20
ESE
25
N
20
NNE
15
NNE
Wind State
cross-on
on
cross-on
cross-off
cross-off
cross-off
off
cross-off
off
off
cross-off
cross-off
off
cross-off
cross-off
cross
off
off
off
High Tide
6:45AM1.29m
6:03PM1.43m
7:26AM1.19m
6:22PM1.41m
8:14AM1.09m
6:42PM1.37m
9:27AM0.99m
7:03PM1.31m
7:24PM1.24m
7:46PM1.15m
Low Tide
00:19AM0.26m
12:11PM0.69m
00:53AM0.27m
12:28PM0.79m
1:31AM0.32m
12:40PM0.87m
2:15AM0.40m
12:34PM0.94m
3:18AM0.48m
5:00AM0.52m
rain showers
thunderstorm
thunderstorm
thunderstorm
light rain
thunderstorm
mod rain
light rain
light rain
light rain
cloud
cloud
light rain
heavy rain
heavy rain
mod rain
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:20
5:20
5:22
5:22
5:22
5:24
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
5:46
5:45
5:44
5:42
5:40
5:38
 mm
4
3
15
4
5
4
6
2
1
2
5
29
15
9
Temp °C
26
25
25
24
23
23
23
20
20
21
21
21
21
23
23
24
23
25
23
Feels °C
27
26
30
28
24
24
24
16
15
16
16
16
17
21
24
24
23
26
24
  • 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