Surf Forecasts:
Onjuku surf forecast from 12 Sep 2026:
- Best quality surf: Saturday 19 Sep, 6PM (local time) - 8ft (2.5m), 12s period, SE swell with cross-offshore winds.
- Most powerful swell: Saturday 19 Sep, 9AM (local time) - 10ft (3.0m), 13s period, SE swell with 3,041 kJ wave energy.
- Next surfable swell (1★+): Sunday 13 Sep, 9AM (local time) - 3ft (0.9m), 13s period with ESE 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 Sunday (Sep 13) at 9AM. The primary swell is predicted to be 0.9m and 13s period with a secondary swell of 0.7m and 6s. Another secondary swell of 0.8m and 6s is also forecast. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 3.0m 13s and forecast to arrive on Saturday (Sep 19) at 9AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 6s period and expected on Thursday (Sep 17) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9AM (Sun 13th Sep) | 3ft (0.9m) 13s |
| Best Surf | 6PM (Sat 19th Sep) | 8ft (2.5m) 12s |
| Most Powerful | 9AM (Sat 19th Sep) | 10ft (3.0m) 13s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright mate, Rusty here with the lowdown for Onjuku over the next 16 days. The water temp's around 80°, so pretty normal for now. It's not going to be a straight-forward run; there's some solid swell coming, but a heap of wind to work around too.
The one bright spot in the near-term is Sunday the 13th. Morning session looks like your best bet, with a clean 3ft wave from the ESE at a nice 13-second interval. The wind is a light offshore breeze from the north at 9 mph, and the energy is moderate (338). It's small but it'll be glassy and fun. Don't get caught out in the arvo when the wind switches.
After that, it's a bit of a write-off for a while. From Monday the 14th most of the way through Friday the 18th, it's a mix of onshore wind, weak short-period junk, or winds so strong it's a mission just to paddle out. By Friday the 18th, the swell is a solid 8ft but the period is only 8 seconds and the offshore wind is a strong 25 mph, making it hard work for all but the fittest.
Now, for the real highlights. If you're an experienced surfer, circle Sunday the 20th. The afternoon looks insane: offshore wind from the north at 12 mph, a solid 10ft swell from the SE with a decent 10-second period, and the combined energy is pumping at 1706. The report says excellent for experienced surfers. That'll be a big, clean, powerful wave. Monday the 21st morning is also clean and solid, a bit smaller at around 6ft, but still quality.
The middle of the second week looks messy again with strong winds, but the end of the run on Monday the 28th afternoon looks like a cracker for the experts. You've got a clean, moderate offshore breeze from the NNE at 12 mph, a 8ft swell from the SSW, and the period is super long at 17 seconds. The energy reading is huge, 4550. That's some serious groundswell. Just remember, that long period might make it a bit fat and closey at a beach break like Onjuku, but for a powerful bank, it'll be magic.
Bottom line: the 20th of September and the 28th are your standout days for the big-wave crew. The rest is a waiting game.
Rusty.
Short Range ForecastModerate rain (total 15mm), heaviest on Tue morning. Warm (max 27°C on Mon morning, min 22°C on Sun morning). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 27mm), heaviest during Wed morning. Warm (max 23°C on Wed morning, min 18°C on Fri morning). Winds increasing (light winds from the NNE on Wed morning, strong winds from the N by Fri morning). | ||||||||||||||||||||
Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | Saturday 19 | |||||||||||||||
AM | 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) | ESE 13 | ESE 13 | E 12 | SSE 10 | SE 9 | SE 9 | E 14 | E 14 | SE 7 | E 13 | E 12 | E 12 | ENE 6 | ENE 7 | ENE 8 | ENE 8 | ENE 8 | SE 15 | SE 13 | SE 12 | SE 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 242 | 178 | 108 | 107 | 147 | 231 | 195 | 196 | 171 | 215 | 148 | 138 | 207 | 345 | 469 | 566 | 590 | 1850 | 3041 | 2160 | 1528 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | off | off | cross-off | cross-off | cross-off |
High Tide | 5:26PM1.43m | 6:04AM1.38m | 5:44PM1.44m | 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 | |||||||||
Low Tide | 11:26AM0.45m | 11:46PM0.30m | 11:50AM0.57m | 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 | |||||||||
 |  |  | | |  |  | |  | |  |  |  |  | | | |  | | |  | |
 | 5:18 | — | — | 5:18 | — | — | 5:20 | — | — | 5:20 | — | — | 5:22 | — | — | 5:22 | — | — | 5:22 | — | — |
 | — | 5:49 | — | — | 5:47 | — | — | 5:46 | — | — | 5:45 | — | — | 5:44 | — | — | 5:42 | — | — | 5:40 | — |
mm | — | — | — | — | — | 3 | 4 | 3 | 5 | 16 | 6 | — | — | 1 | 3 | 1 | — | — | 1 | 5 | 35 |
Temp °C | 24 | 24 | 26 | 27 | 27 | 25 | 25 | 26 | 25 | 23 | 23 | 23 | 23 | 22 | 20 | 19 | 19 | 21 | 23 | 24 | 22 |
Feels °C | 28 | 28 | 29 | 28 | 27 | 26 | 26 | 28 | 29 | 24 | 24 | 23 | 21 | 19 | 15 | 13 | 14 | 19 | 23 | 24 | 23 |
Swell 1 Height (m) Direction Period (s) | ESE 13 | ESE 13 | ESE 9 | ESE 9 | SE 9 | SE 9 | SE 8 | SE 8 | SE 7 | E 13 | SE 8 | E 12 | E 12 | E 11 | E 12 | E 12 | SE 18 | SE 15 | SE 13 | SE 12 | SE 11 |
| kJ | 242 | 178 | 52 | 45 | 147 | 231 | 177 | 129 | 171 | 215 | 69 | 138 | 67 | 60 | 43 | 26 | 570 | 1850 | 3041 | 2160 | 1528 |
Swell 2 Height (m) Direction Period (s) | NE 6 | SE 9 | E 12 | E 12 | E 12 | E 14 | E 14 | E 14 | E 13 | SSE 7 | E 12 | SE 8 | SSE 10 | E 13 | SSE 9 | SE 20 | E 11 | ESE 9 | ENE 10 | ENE 10 | S 14 |
| kJ | 38 | 46 | 108 | 76 | 112 | 189 | 195 | 196 | 167 | 66 | 148 | 54 | 9 | 14 | 8 | 16 | 22 | 232 | 386 | 318 | 36 |
Swell 3 Height (m) Direction Period (s) | SSW 7 | ENE 6 | SSE 7 | NE 6 | ENE 7 | ENE 7 | ENE 7 | NE 10 | SW 5 | SE 9 | E 18 | E 16 | E 15 | SSE 9 | — | SE 8 | SSE 8 | — | — | — | — |
| kJ | 5 | 25 | 19 | 10 | 9 | 10 | 5 | 4 | 25 | 29 | 6 | 5 | 17 | 8 | — | 3 | 7 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | NE 6 | — | — | SSE 10 | SSW 4 | S 7 | — | S 3 | — | NE 5 | NE 5 | ENE 6 | ENE 6 | ENE 7 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | — | — | ENE 9 |
| kJ | 53 | — | — | 107 | 11 | 1 | — | 5 | — | 26 | 56 | 103 | 207 | 345 | 469 | 566 | 590 | 375 | — | — | 232 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 9 | 9 | 143 | 583 | 110 | 23 | 17 | 0 | 22 | 16 | 56 | 206 | 206 | 295 | 295 | 536 | 295 | 553 | 84 | 51 |
Best forecast wave conditions in Chiba | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
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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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