Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 2 am 20 Sep 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
24.5°C
1.1° 

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


Onjuku surf forecast from 19 Sep 2026:

  • Best quality surf: Monday 21 Sep, 6AM (local time) - 11ft (3.5m), 12s period, SSE swell with cross-shore winds.
  • Most powerful swell: Tuesday 22 Sep, 3AM (local time) - 26ft (8.0m), 16s period, SSE swell with 32,262 kJ wave energy.
  • Next surfable swell (1★+): Monday 21 Sep, 3AM (local time) - 10ft (3.0m), 12s period with SSE 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 Monday (Sep 21) at 3AM. The primary swell is predicted to be 3.0m and 12s period with a secondary swell of 0.5m and 12s. 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 8.0m 16s and forecast to arrive on Tuesday (Sep 22) 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 1.4m 5s period and expected on Tuesday (Sep 22) at 6AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Mon 21st Sep)10ft (3.0m) 12s
Best Surf 6AM (Mon 21st Sep)11ft (3.5m) 12s
Most Powerful 3AM (Tue 22nd Sep)26ft (8.0m) 16s

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


Short Range Forecast

Heavy rain (total 160mm), heaviest during Mon night. Warm (max 28°C on Tue morning, min 22°C on Sun morning). Winds decreasing (gales from the ESE on Mon night, light winds from the E by Tue afternoon).

Days 4-6 Weather Summary

Light rain (total 2mm), mostly falling on Fri night. Warm (max 26°C on Fri morning, min 22°C on Wed afternoon). Wind will be generally light.

Sunday
20
Monday
21
Tuesday
22
Wednesday
23
Thursday
24
Friday
25
Saturday
26
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
2
2
3
0
0
!
4
2
0
0
1
2
0
0
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)
3
SE
12
3
SE
11
3
SE
11
4
S
12
4
SSE
12
7
SSW
15
3
SSE
11
2.4
SSW
9
1.5
SSE
8
0.9
SSE
7
1.2
ENE
9
1.2
ENE
8
1
ESE
6
0.9
ESE
6
0.9
ESE
6
1.1
SE
6
1.2
SE
6
1
SE
6
1
ESE
7
1
ESE
7
1
E
7
Wave Graph
Metric surfscale
Energy kJ
2132
2155
2548
4286
4493
21858
2320
933
286
91
227
190
74
59
57
101
96
75
91
102
106
Wind (km/h)
35
NNE
30
NNE
25
NE
25
SE
35
SE
65
ESE
15
W
10
SSW
30
NE
25
NE
25
NE
15
NE
15
NE
15
ENE
10
ENE
10
E
10
SE
15
SSW
25
SW
25
SW
25
NE
Wind State
cross-off
cross-off
cross-off
cross-on
cross-on
cross
cross
cross-on
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross
cross-on
cross-on
cross-on
cross-on
cross-off
High Tide
7:46PM1.15m
3:28PM1.16m
11:46PM1.11m
3:22PM1.21m
1:26AM1.17m
3:32PM1.27m
2:24AM1.25m
3:45PM1.32m
3:10AM1.33m
4:01PM1.37m
3:52AM1.40m
4:19PM1.41m
Low Tide
6:47AM0.49m
8:11PM1.06m
7:49AM0.43m
8:35PM0.94m
8:31AM0.37m
9:01PM0.82m
9:06AM0.34m
9:27PM0.68m
9:37AM0.33m
9:55PM0.54m
10:07AM0.37m
10:24PM0.40m
heavy rain
light rain
heavy rain
thunderstorm
thunderstorm
thunderstorm
rain showers
part cloud
part cloud
part cloud
cloud
part cloud
cloud
clear
part cloud
cloud
part cloud
thunderstorm
clear
rain showers
light rain
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:24
5:24
5:24
5:26
5:26
5:26
5:28
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
5:38
5:37
5:36
5:35
5:34
5:31
5:30
 mm
31
4
15
15
14
80
1
2
1
1
Temp °C
22
23
25
27
27
27
28
26
25
23
22
23
22
23
24
26
26
25
26
26
22
Feels °C
19
23
29
29
27
24
30
29
25
21
19
23
21
23
25
26
27
27
25
26
21
  • 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
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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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