Onjuku Surf Break

Lat Long: 35.18° N 140.35° E

Onjuku Surf Forecast and Surf Report

Issued: 8 pm 15 Jul 2026 (local time)

Forecast update in  hr  min

Today's Onjuku sea temperature is
25.3° C
0.1° 

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


Onjuku surf forecast from 15 Jul 2026:

  • Best quality surf: Monday 20 Jul, 3AM (local time) - 3.5ft (1.1m), 9s period, E swell with glassy winds.
  • Most powerful swell: Tuesday 21 Jul, 12AM (local time) - 5ft (1.6m), 12s period, E swell with 714 kJ wave energy.
  • Next surfable swell (1★+): Monday 20 Jul, 3AM (local time) - 3.5ft (1.1m), 9s 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 Monday (Jul 20) at 3AM. The primary swell is predicted to be 1.1m and 9s period with a secondary swell of 0.4m 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 1.6m 12s and forecast to arrive on Tuesday (Jul 21) at 12AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 6s period and expected on Wednesday (Jul 22) at 9PM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+) 3AM (Mon 20th Jul)3.5ft (1.1m) 9s
Best Surf 3AM (Mon 20th Jul)3.5ft (1.1m) 9s
Most Powerful12AM (Tue 21st Jul)5ft (1.6m) 12s

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


The Lowdown

Alright, Rusty here, and I’ve got the lowdown on what’s heading our way for Onjuku. Gotta be straight with you—this one’s a bit of a slow burner. We’re looking at a real flat and choppy spell to kick things off, so don’t bother waxing up just yet.

Things start off rough. Thursday the 16th and Friday the 17th are a write-off. We’ve got a tiny 3 ft swell out of the ESE and E, but the wind is all over it—onshore and cross-onshore, making for poor, bumpy conditions. The combined energy is weak, sitting around 140 to 175 (weak energy). Not worth paddling out.

We stay in the doldrums through Saturday the 18th. The swell bumps up slightly to 3 ft from the ESE, but that cross-onshore wind is still messing it up. Wave energy is still low, in the 200s (moderate energy). Not fun.

Sunday the 19th sees a tiny glimmer. The morning brings a 4 ft ESE swell with a light onshore wind, and the combined energy climbs to 282 (moderate energy). It’s still marginal—tide might be an issue—but it’s the first time we get a score above a zero. The afternoon looks even better with clear skies and a light S breeze, keeping the 4 ft swell cleaner, but it’s still just marginal.

Monday the 20th is a tease. Morning is 4 ft from the E, light cross-onshore wind, but the energy is only 258 (moderate). The afternoon has a bigger 4 ft swell from the E with a 10-second period, and the energy jumps to 367 (moderate energy), but the wind is onshore and stronger. Still poor.

Now listen up, because Wednesday the 22nd is where things get interesting. The wind finally shifts offshore, coming out of the NE at 19 mph in the morning. We’ve got a 4 ft E swell with an 11-second period, and the energy is 396 (moderate energy). The report says “clean” for the first time. Onshore wind? Gone. This is your first real chance for some clean, lined-up waves. Thursday the 23rd morning is another standout: a 4 ft E swell, 10-second period, with a gentle ENE offshore breeze. The energy is 330 (moderate) and the surf condition is marked as “good.” That’s your best bet early on—clean, workable waves at Onjuku.

After that, it goes back to choppy onshore junk through the 24th and 25th, with small swells in the 3 ft to 4 ft range and onshore winds.

The end of the run has a big, messy swell. On Monday the 28th, we get a 6 ft swell from the S with a long 14-second period. The combined energy is a massive 1405 (strong to very strong wave energy). That’s a lot of water moving. But—and this is a big but—the winds are cross-onshore and strong, 12-19 mph. That much energy with that wind will be a lumpy, choppy mess. Too big for beginners (over 5 ft) and the wind will kill any chance of a clean face. This is more of a kite-surfing setup than a paddle-surfing one at a beach break.

Overall, the one to circle is Thursday morning, July 23rd. The wind is light offshore, the swell is a manageable 4 ft from the east, and the energy is solid enough. It’ll be the cleanest wave of the whole period. It’s an exposed beach, and it’s listed as “inconsistent,” so you’ll need patience between sets, but it’s the only time the stars align. Get it while it’s good.

- Rusty

Short Range Forecast

Light rain (total 2mm), mostly falling on Thu night. Warm (max 28°C on Thu morning, min 25°C on Fri night). Wind will be generally light.

Days 5-7 Weather Summary

Mostly dry. Warm (max 28°C on Tue morning, min 24°C on Sat night). Wind will be generally light.

Thursday
16
Friday
17
Saturday
18
Sunday
19
Monday
20
Tuesday
21
Wed
22
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Rating
(10 max)
0
0
0
0
0
0
0
0
0
1
1
1
1
1
0
1
0
0
0
0
1
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.8
E
9
0.8
ESE
8
0.8
ESE
9
0.9
ESE
8
0.9
E
8
0.8
E
8
0.9
ESE
8
1.1
ESE
9
1
ESE
9
1.1
ESE
9
1.3
ESE
9
1.2
ESE
9
1.1
E
9
1.2
E
9
1.3
E
10
1.6
E
12
1.5
E
12
1.5
E
11
1.4
E
11
1.3
E
11
1.2
E
11
Wave Graph
Metric surfscale
Energy kJ
99
96
99
118
116
90
115
176
169
206
266
248
189
241
314
714
586
566
457
379
317
Wind (km/h)
30
SSW
15
SSW
20
S
20
SSE
20
SSE
15
SE
15
SSE
15
SE
15
SSE
10
SSE
5
SSE
10
S
5
SW
10
SSW
20
SSW
15
SW
15
SSW
25
SSW
10
SW
30
NE
25
NE
Wind State
on
on
on
on
cross-on
cross-on
cross-on
cross-on
on
on
on
on
cross-on
cross-on
on
cross-on
cross-on
cross-on
cross-on
cross-off
cross-off
High Tide
4:33AM1.52m
6:54PM1.36m
5:24AM1.49m
7:20PM1.34m
6:15AM1.41m
7:45PM1.33m
7:06AM1.30m
8:08PM1.33m
8:01AM1.17m
8:32PM1.33m
9:07AM1.04m
8:57PM1.32m
10:41AM0.95m
Low Tide
11:12PM0.96m
11:51AM-0.03m
11:55PM0.87m
12:29PM0.08m
00:40AM0.77m
1:04PM0.23m
1:26AM0.69m
1:34PM0.40m
2:16AM0.63m
2:01PM0.57m
3:11AM0.58m
2:24PM0.72m
4:14AM0.54m
2:41PM0.85m
part cloud
part cloud
part cloud
thunderstorm
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
clear
part cloud
clear
clear
clear
clear
clear
thunderstorm
clear
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:35
4:35
4:35
4:37
4:37
4:37
4:39
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:52
6:52
6:52
6:52
6:51
6:51
6:50
6:50
 mm
2
3
Temp °C
26
28
28
26
27
27
26
27
27
25
27
27
25
27
27
25
28
28
26
27
26
Feels °C
27
31
31
29
29
29
29
29
29
27
29
30
28
28
28
27
30
29
29
27
26
  • 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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