Surf Forecasts:
Onjuku surf forecast from 29 Aug 2026:
- Best quality surf: Tuesday 1 Sep, 12AM (local time) - 2.5ft (0.8m), 12s period, ESE swell with offshore winds.
- Most powerful swell: Friday 4 Sep, 3PM (local time) - 7ft (2.2m), 8s period, ENE swell with 650 kJ wave energy.
- Next surfable swell (1★+): Saturday 29 Aug, 6PM (local time) - 1.5ft (0.5m), 11s 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 Saturday (Aug 29) at 6PM. The primary swell is predicted to be 0.5m and 11s period with a secondary swell of 0.4m and 11s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 2.2m 8s and forecast to arrive on Friday (Sep 04) at 3PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Friday (Sep 04) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Sat 29th Aug) | 1.5ft (0.5m) 11s |
| Best Surf | 12AM (Tue 1st Sep) | 2.5ft (0.8m) 12s |
| Most Powerful | 3PM (Fri 4th Sep) | 7ft (2.2m) 8s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright mate, let’s break down what’s happening at Onjuku over the next couple weeks. It’s gonna be a story of waiting for the good stuff.
Water temp is about 82°, so a touch warmer than usual. Not bad.
First few days are a write-off. Saturday the 29th and Sunday the 30th have tiny, junky surf with onshore winds. You’re better off grabbing a coffee. Monday the 31st stays small, with a 2ft east swell and a period around 11 seconds – clean in the morning thanks to a bit of offshore breeze, but still not worth getting wet for. There’s a real lull there.
Then Tuesday the 1st of September wakes things up. Swell bumps to 3ft from the ESE, period around 12 seconds, and the wind goes light and variable in the morning, turning glassy by the afternoon. That’s your first proper window. Combined energy sits at a solid 319. Be ready for some company though – Onjuku can get busy.
Wednesday the 2nd drops off, and then we hit a long stretch of poor quality through the rest of the first week. Swell peaks a bit on Friday the 4th and Saturday the 5th, but the wind is either onshore or too strong cross-off. The waves get up to around 7ft on Friday afternoon with energy in the 747 range, but the conditions are rough – might be more interesting for the kite crew than paddle surfers.
Now, the standout is a bit further out. On Saturday the 12th of September, the morning looks like a winner for anyone with some experience. Swell is 6ft from the ENE at 10 seconds, with a strong offshore from the north-northwest. The combined energy is a hefty 1107. It’s clean, it’s punchy, and it’s the best bet on the board. A bit of a wait, but worth keeping an eye on.
After that, the swell hangs around but the wind turns onshore again, and the quality fades. So, make plans for Tuesday the 1st for a small, clean session, and keep the 12th of September circled for the real deal.
Rusty.
Short Range ForecastLight rain (total 9mm), mostly falling on Sat morning. Warm (max 27°C on Mon morning, min 22°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 6mm), mostly falling on Wed night. Warm (max 28°C on Wed morning, min 25°C on Tue night). Wind will be generally light. | ||||||||||||||||||||
Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | |||||||||||||||
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) | E 12 | E 11 | E 11 | E 11 | E 11 | E 11 | E 11 | ESE 14 | ESE 12 | ESE 12 | ESE 11 | ESE 11 | ESE 10 | SE 6 | SE 6 | E 12 | E 11 | E 10 | S 10 | ENE 8 | ENE 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 96 | 63 | 58 | 59 | 60 | 56 | 56 | 73 | 175 | 242 | 186 | 167 | 116 | 101 | 109 | 71 | 114 | 96 | 92 | 650 | 336 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | off | cross-off | cross-off | off | off | cross-off | off | off | glassy | cross-on | cross-on | on | on | on | on | cross-on | cross-off | cross-off | cross-off |
High Tide | 5:32PM1.40m | 5:17AM1.43m | 5:51PM1.42m | 5:58AM1.39m | 6:10PM1.43m | 6:41AM1.32m | 6:31PM1.44m | 7:30AM1.23m | 6:53PM1.43m | 8:31AM1.12m | 7:17PM1.40m | 10:14AM1.02m | 7:46PM1.36m | ||||||||
Low Tide | 11:09AM0.24m | 11:22PM0.53m | 11:35AM0.32m | 11:54PM0.43m | 12:02PM0.43m | 00:30AM0.36m | 12:27PM0.56m | 1:09AM0.32m | 12:52PM0.70m | 1:54AM0.31m | 1:12PM0.84m | 2:52AM0.34m | 1:18PM0.97m | ||||||||
 |  |  |  |  |  | | | | | |  |  | |  | | | | | |  | |
 | 5:07 | — | — | 5:07 | — | — | 5:09 | — | — | 5:09 | — | — | 5:11 | — | — | 5:11 | — | — | 5:11 | — | — |
 | — | 6:09 | — | — | 6:08 | — | — | 6:07 | — | — | 6:06 | — | — | 6:05 | — | — | 6:04 | — | — | 6:01 | — |
mm | 5 | 2 | — | — | — | — | 2 | — | — | — | — | — | — | — | 4 | 2 | — | — | — | — | 17 |
Temp °C | 26 | 26 | 23 | 26 | 25 | 24 | 27 | 27 | 25 | 26 | 26 | 26 | 28 | 28 | 27 | 28 | 28 | 27 | 24 | 24 | 22 |
Feels °C | 29 | 30 | 24 | 28 | 27 | 27 | 30 | 28 | 27 | 30 | 31 | 31 | 31 | 31 | 31 | 29 | 30 | 29 | 24 | 22 | 21 |
Swell 1 Height (m) Direction Period (s) | E 12 | E 5 | SSW 7 | ENE 6 | ENE 6 | E 6 | E 6 | ESE 14 | ESE 12 | ESE 12 | E 7 | ESE 11 | ESE 10 | ESE 6 | SE 6 | SE 6 | E 11 | SSE 6 | S 10 | S 9 | E 9 |
| kJ | 96 | 28 | 26 | 49 | 43 | 39 | 30 | 73 | 175 | 242 | 83 | 167 | 116 | 64 | 109 | 68 | 114 | 67 | 92 | 41 | 44 |
Swell 2 Height (m) Direction Period (s) | S 8 | E 11 | E 11 | E 11 | E 11 | E 11 | E 11 | E 11 | E 10 | ENE 6 | ESE 11 | E 7 | E 6 | ESE 10 | ESE 10 | E 9 | S 9 | E 10 | E 10 | SSW 11 | S 10 |
| kJ | 18 | 63 | 58 | 59 | 60 | 56 | 56 | 36 | 35 | 53 | 186 | 58 | 41 | 77 | 74 | 45 | 40 | 96 | 70 | 43 | 54 |
Swell 3 Height (m) Direction Period (s) | SE 11 | SE 11 | SE 10 | SE 10 | SE 10 | SE 10 | NE 7 | SE 9 | SSW 9 | SSW 8 | SSW 9 | SSW 9 | SSW 8 | SSW 8 | SSW 9 | E 12 | SSW 12 | S 11 | SE 7 | SE 9 | SE 9 |
| kJ | 30 | 30 | 27 | 26 | 26 | 26 | 17 | 22 | 16 | 24 | 26 | 25 | 24 | 24 | 27 | 71 | 30 | 85 | 35 | 13 | 13 |
Wind waves Height (m) Direction Period (s) | E 4 | — | NE 6 | — | ENE 6 | — | — | ENE 6 | ENE 6 | NNE 7 | — | — | — | SE 6 | — | S 8 | SE 6 | — | NE 6 | ENE 8 | ENE 8 |
| kJ | 15 | — | 86 | — | 64 | — | — | 64 | 68 | 41 | — | — | — | 101 | — | 51 | 83 | — | 178 | 650 | 336 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 45 | 9 | 0 | 12 | 0 | 0 | 0 | 45 | 0 | 0 | 0 | 9 | 9 | 9 | 9 | 9 | 9 | 84 | 51 | 51 | 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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