Surf Forecasts:
Onjuku surf forecast from 5 Aug 2026:
- Best quality surf: Tuesday 11 Aug, 6AM (local time) - 11ft (3.5m), 12s period, NE swell with offshore winds.
- Most powerful swell: Tuesday 11 Aug, 9PM (local time) - 13ft (4.0m), 11s period, NE swell with 4,069 kJ wave energy.
- Next surfable swell (1★+): Thursday 6 Aug, 12AM (local time) - 10ft (3.0m), 13s period with SE 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 Thursday (Aug 06) at 12AM. The primary swell is predicted to be 3.0m and 13s period with a secondary swell of 0.2m and 16s. 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 4.0m 11s and forecast to arrive on Tuesday (Aug 11) at 9PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 3.0m 8s period and expected on Wednesday (Aug 12) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Thu 6th Aug) | 10ft (3.0m) 13s |
| Best Surf | 6AM (Tue 11th Aug) | 11ft (3.5m) 12s |
| Most Powerful | 9PM (Tue 11th Aug) | 13ft (4.0m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
G'day, Rusty here. Let's have a look at what’s on offer for Onjuku over the next couple of weeks.
Right off the bat, we’ve got a real beast of a swell rolling in on Wednesday the 5th of August. The ocean is absolutely pumping with a huge 12ft SE swell, packing some serious grunt with a combined energy of 4566 (moderate wave energy). The wind is a cross-off from the NE at 15 mph, which will keep the surface clean, but honestly, this is too much juice for most. At that size, you’d want to be well experienced and on the right craft. The water's sitting at 78°, which is about average for this time of year.
Thursday the 6th is where it's at for the experienced crew. The swell drops to a still solid 7ft from the SSE, with a lovely 13-second period. The combined energy is still strong at 1955 (moderate wave energy). The morning session is the call with a clean cross-off breeze from the ENE at 9 mph. This is excellent surf for those who know what they're doing.
After that, things get a bit messy for a good stretch. From Thursday afternoon right through to the end of the second week, the surf quality really drops off. The wind turns onshore or cross-onshore, and the wave heights drop, making for mostly choppy, poor conditions. There’s a long gap of pretty average surf from the 6th afternoon all the way to the 20th of August.
There is a glimmer out on the 18th of August, Tuesday morning. We get a little 4ft ESE swell, but the period is a short, weak 7 seconds, so the energy is low at 310 (weak wave energy). The wind is a light offshore breeze, so it'll be clean, but it's really only a small, weak wave for a longboard or a learner.
The standout is easily the Thursday morning session on the 6th of August at Onjuku. It's big, powerful, and clean for the experienced surfer. Don't sleep on that if you've got the skills.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Thu afternoon. Warm (max 28°C on Thu morning, min 24°C on Wed night). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 10mm), heaviest on Tue morning. Warm (max 27°C on Sat afternoon, min 23°C on Sun night). Winds increasing (calm on Sat night, near gales from the NNE by Tue morning). | |||||||||||||||||||
Wed 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | ||||||||||||||
PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map |  |  |  |  |  |  |  | |||||||||||||
Wave Height (m) Direction Period (s) | SE 14 | SE 13 | SSE 13 | SSE 12 | S 13 | S 13 | S 13 | S 13 | S 13 | ESE 13 | ESE 13 | ESE 14 | ESE 13 | E 12 | E 12 | ENE 11 | ENE 10 | ENE 11 | ENE 11 | NE 11 |
Wave Graph  | ||||||||||||||||||||
 kJ | 4542 | 2795 | 1572 | 1405 | 1693 | 1215 | 1090 | 852 | 613 | 569 | 700 | 1075 | 946 | 799 | 915 | 1167 | 2007 | 1302 | 1520 | 3786 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross-on | glassy | cross-off | cross-off | cross-off | cross-off | cross-off | off | off | cross-off | cross-off |
High Tide | 8:17PM1.37m | 9:58AM1.02m | 8:49PM1.35m | 12:56PM1.00m | 9:31PM1.33m | 10:43PM1.31m | 4:10PM1.23m | 00:23AM1.32m | 4:33PM1.30m | 1:48AM1.37m | 4:57PM1.35m | 2:54AM1.44m | ||||||||
Low Tide | 3:27AM0.45m | 2:20PM0.85m | 4:43AM0.41m | 2:29PM1.00m | 6:13AM0.33m | 7:36AM0.23m | 7:43PM1.16m | 8:40AM0.12m | 8:57PM1.09m | 9:31AM0.04m | 9:44PM0.99m | |||||||||
 |  | |  |  | | |  | | | | | | |  | |  |  |  |  | |
 | — | — | 4:50 | — | — | 4:50 | — | — | 4:52 | — | — | 4:52 | — | — | 4:52 | — | — | 4:54 | — | — |
 | 6:38 | — | — | 6:37 | — | — | 6:37 | — | — | 6:36 | — | — | 6:35 | — | — | 6:32 | — | — | 6:31 | — |
mm | — | — | — | 1 | 4 | — | — | — | — | — | — | — | — | — | — | — | 2 | 8 | 5 | 10 |
Temp °C | 25 | 25 | 28 | 28 | 26 | 28 | 28 | 25 | 27 | 27 | 25 | 27 | 26 | 24 | 25 | 25 | 24 | 24 | 24 | 24 |
Feels °C | 25 | 29 | 31 | 31 | 29 | 31 | 31 | 28 | 30 | 29 | 29 | 28 | 26 | 24 | 21 | 21 | 20 | 19 | 19 | 21 |
Swell 1 Height (m) Direction Period (s) | SE 14 | SE 13 | SSE 13 | SSE 12 | S 13 | S 13 | S 13 | S 13 | S 13 | S 12 | ESE 13 | ESE 14 | ESE 13 | E 12 | E 12 | S 11 | ENE 10 | ENE 11 | ENE 11 | ENE 11 |
| kJ | 4542 | 2795 | 1572 | 1405 | 1693 | 1215 | 1090 | 852 | 613 | 530 | 700 | 1075 | 946 | 799 | 915 | 89 | 1202 | 1302 | 1520 | 2005 |
Swell 2 Height (m) Direction Period (s) | E 18 | E 16 | ESE 10 | ESE 10 | ESE 10 | ESE 9 | ESE 10 | ESE 9 | ESE 9 | ESE 13 | S 12 | S 12 | SSW 14 | S 11 | S 11 | SW 14 | S 12 | SSW 13 | SSW 13 | SSW 12 |
| kJ | 24 | 21 | 363 | 351 | 371 | 327 | 284 | 261 | 236 | 569 | 344 | 280 | 514 | 203 | 116 | 102 | 104 | 235 | 212 | 152 |
Swell 3 Height (m) Direction Period (s) | — | E 12 | E 16 | E 16 | E 15 | E 15 | E 15 | E 14 | E 14 | E 14 | ESE 16 | SW 14 | — | SW 15 | SW 14 | SSW 10 | SW 14 | — | SE 13 | — |
| kJ | — | 66 | 20 | 20 | 41 | 39 | 39 | 37 | 35 | 16 | 153 | 132 | — | 183 | 132 | 74 | 95 | — | 7 | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | NE 3 | NNE 4 | ENE 11 | ENE 10 | — | — | NE 11 |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | 5 | 39 | 1167 | 2007 | — | — | 3786 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 56 | 0 | 0 | 9 | 9 | 9 | 103 | 9 | 9 | 9 | 0 | 12 | 51 | 51 | 206 | 2120 | 200 | 200 | 206 | 557 |
Best forecast wave conditions in Chiba | ||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||
Header Global | ||||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
Latest Updates
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