Surf Forecasts:
Onjuku surf forecast from 7 Aug 2026:
- Best quality surf: Friday 14 Aug, 3AM (local time) - 13ft (4.0m), 11s period, E swell with offshore winds.
- Most powerful swell: Friday 14 Aug, 3AM (local time) - 13ft (4.0m), 11s period, E swell with 3,426 kJ wave energy.
- Next surfable swell (1★+): Sunday 9 Aug, 3AM (local time) - 5.5ft (1.7m), 14s 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 (Aug 09) at 3AM. The primary swell is predicted to be 1.7m and 14s period with a secondary swell of 0.9m and 11s. The wind is predicted to be glassy 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 Friday (Aug 14) 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 1.3m 5s period and expected on Monday (Aug 10) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Sun 9th Aug) | 5.5ft (1.7m) 14s |
| Best Surf | 3AM (Fri 14th Aug) | 13ft (4.0m) 11s |
| Most Powerful | 3AM (Fri 14th Aug) | 13ft (4.0m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s on the cards for Onjuku over the next couple of weeks.
The first window of decent surf isn’t until Sunday morning, August 9th, so we’ve got a bit of a wait. Thursday and Friday are a write-off – stormy, onshore, just ugly. Saturday’s a bit of a tease with some small, cross-onshore slop that’s hard to get excited about.
But then Sunday (August 9th) and Sunday arvo, things clean up nicely. We’ve got a solid 6 ft swell rolling in from the ESE with a 13-second period, which has some real push to it. The combined energy reading is strong (1133), and the wind is a light, cross-offshore breeze. The water is a bit colder than normal for this time of year, sitting at 76°, which is a notable 4° below average. It’s clean, it’s got length, and it’s the best call for the intermediate crew. Keep in mind it’s inconsistent, so patience is the key.
Monday (August 10th) gets bigger – 7 ft to 8 ft from the E – but that fresh wind makes it a bit of a handful. It’s still cross-offshore, so it’s not a total loss, but the conditions are marginal. Tuesday (August 11th) drops off with a messy cross-shore wind, and by Wednesday (August 12th) the swell fades to a small 3 ft, although it’s clean. A few days of small, clean waves follow.
Now, the real standout is a long way out, but it’s worth a mention. On Friday, August 21st, the wind goes glassy in the morning, and we’ve got an 8 ft swell from the NE. The combined energy is strong (1671), and it’s described as excellent for experienced surfers. That’s a big one. But the true gem is Saturday, August 22nd morning. We’re talking 10 ft of NE swell, 11-second period, and a massive energy reading of 3680. The wind is a gentle, clean cross-offshore. This is the best wave of the whole forecast period – solid, powerful, and clean. It’s big, so it’s strictly for the experienced crew. Crowds are possible here, so get there early if you can.
The rest of the second week sees a mix of dropping swell and onshore winds, so that Saturday morning is the one to circle.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri morning. Warm (max 28°C on Fri morning, min 23°C on Sun night). Winds increasing (calm on Sat night, fresh winds from the NNE by Sun night). | Days 4-6 Weather SummaryHeavy rain (total 32mm), heaviest during Tue night. Warm (max 27°C on Mon morning, min 23°C on Mon night). Winds decreasing (fresh winds from the NE on Mon afternoon, light winds from the WNW by Mon night). | ||||||||||||||||||||
Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | |||||||||||||||
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) | S 12 | S 12 | S 11 | S 11 | ESE 13 | ESE 14 | ESE 13 | ESE 13 | ESE 12 | E 12 | E 11 | ENE 11 | E 12 | E 11 | E 10 | E 9 | E 8 | E 10 | E 11 | E 12 | E 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 948 | 617 | 457 | 350 | 624 | 1053 | 998 | 903 | 781 | 1324 | 1293 | 1027 | 1040 | 676 | 284 | 166 | 142 | 450 | 1037 | 1517 | 2521 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | on | cross-on | cross-on | on | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross | cross-on | cross-on | cross-off | cross-off | off | cross-off | cross-off | off |
High Tide | 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 | 5:21PM1.37m | 3:50AM1.49m | 5:43PM1.38m | |||||||||
Low Tide | 2:29PM1.00m | 6:13AM0.33m | 7:36AM0.23m | 7:43PM1.16m | 8:40AM0.12m | 8:57PM1.09m | 9:31AM0.04m | 9:44PM0.99m | 10:15AM0.00m | 10:23PM0.88m | 10:54AM0.03m | 11:01PM0.75m | |||||||||
 |  |  | | | | |  |  | | | |  |  |  | | | | | |  | |
 | 4:50 | — | — | 4:52 | — | — | 4:52 | — | — | 4:52 | — | — | 4:54 | — | — | 4:54 | — | — | 4:56 | — | — |
 | — | 6:37 | — | — | 6:36 | — | — | 6:35 | — | — | 6:32 | — | — | 6:31 | — | — | 6:30 | — | — | 6:30 | — |
mm | 2 | — | — | — | — | — | — | — | — | — | — | — | — | 2 | 24 | 6 | — | — | 5 | 7 | 1 |
Temp °C | 28 | 28 | 26 | 27 | 27 | 25 | 27 | 27 | 24 | 27 | 26 | 23 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 24 |
Feels °C | 31 | 30 | 29 | 30 | 28 | 28 | 27 | 28 | 25 | 25 | 23 | 22 | 26 | 25 | 24 | 26 | 27 | 28 | 27 | 28 | 24 |
Swell 1 Height (m) Direction Period (s) | S 12 | S 12 | S 11 | S 11 | ESE 13 | ESE 14 | ESE 13 | ESE 13 | ESE 12 | E 12 | S 11 | ENE 11 | E 12 | E 11 | E 10 | E 9 | E 8 | E 10 | S 10 | S 10 | E 11 |
| kJ | 948 | 617 | 457 | 350 | 624 | 1053 | 998 | 903 | 781 | 1324 | 88 | 1027 | 1040 | 676 | 284 | 166 | 142 | 450 | 54 | 52 | 2521 |
Swell 2 Height (m) Direction Period (s) | ESE 9 | ESE 9 | ESE 9 | ESE 9 | S 11 | S 11 | S 10 | S 10 | S 10 | SSW 12 | SW 12 | S 10 | S 10 | S 11 | SSW 11 | SSW 11 | S 11 | SSW 10 | SSE 9 | — | SSW 10 |
| kJ | 327 | 282 | 288 | 236 | 282 | 188 | 135 | 138 | 74 | 106 | 83 | 53 | 53 | 85 | 102 | 128 | 88 | 86 | 8 | — | 33 |
Swell 3 Height (m) Direction Period (s) | E 15 | E 15 | E 14 | E 14 | E 10 | SW 14 | — | SW 12 | SW 12 | SW 12 | SSE 11 | SW 12 | SW 12 | SW 12 | SW 12 | SSW 5 | SSW 5 | — | — | — | SSE 12 |
| kJ | 39 | 39 | 37 | 36 | 46 | 29 | — | 65 | 23 | 114 | 11 | 23 | 23 | 23 | 144 | 7 | 2 | — | — | — | 13 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | NNE 5 | E 11 | NE 8 | — | SSW 3 | SSE 4 | ENE 4 | NE 4 | — | E 11 | E 12 | — |
| kJ | — | — | — | — | — | — | — | — | — | 83 | 1293 | 530 | — | 10 | 36 | 16 | 17 | — | 1037 | 1517 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 9 | 9 | 9 | 9 | 9 | 0 | 0 | 22 | 51 | 51 | 22 | 18 | 553 | 143 | 51 | 51 | 0 | 206 | 51 | 553 |
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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