Surf Forecasts:
Onjuku surf forecast from 6 Sep 2026:
- Best quality surf: Wednesday 9 Sep, 9PM (local time) - 6.5ft (2.0m), 9s period, S swell with offshore winds.
- Most powerful swell: Monday 7 Sep, 6PM (local time) - 11ft (3.5m), 9s period, S swell with 2,010 kJ wave energy.
- Next surfable swell (1★+): Wednesday 9 Sep, 9PM (local time) - 6.5ft (2.0m), 9s period with S 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 Wednesday (Sep 09) at 9PM. The primary swell is predicted to be 2.0m and 9s period with a secondary swell of 0.2m and 16s. Another secondary swell of 1.8m and 7s 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 3.5m 9s and forecast to arrive on Monday (Sep 07) at 6PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 4s period and expected on Saturday (Sep 12) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Wed 9th Sep) | 6.5ft (2.0m) 9s |
| Best Surf | 9PM (Wed 9th Sep) | 6.5ft (2.0m) 9s |
| Most Powerful | 6PM (Mon 7th Sep) | 11ft (3.5m) 9s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright, Rusty here. Let's have a look at what's cookin' for Onjuku over the next couple weeks.
Honestly, it's a tough stretch for the most part. We're looking at a long, frustrating gap with nothing really worth paddling out for. The first real chance you've got to get wet without hating life doesn't come around until the morning of Thursday the 10th. Before that, it's a write-off. Monday the 8th and Tuesday the 9th are blown out with strong cross-onshore winds and messy, lumpy conditions, so save your energy.
Thursday the 10th morning is where it gets interesting. The wind swings offshore from the NNE at 16 mph, cleaning everything right up. You'll find clean, moderate offshore surf with a chest-high 4 ft swell from the south, but the period is a short 8 seconds, so it'll be a bit soft and crumbly. The combined wave energy is moderate (337), so there's a bit of push behind it. Water temp is sitting at 82°, which is a touch warmer than normal for this time of year. Onjuku itself is inconsistent and can get crowded sometimes, so don't expect a circus. This is your standout window – clean, manageable, and the only proper shot at a decent session for a while.
After that, things drop right off. The swell tanks and the energy just disappears. By the morning of Saturday the 12th, you're looking at knee-to-waist high dribble at best, and it stays that way through the second week. You'll see a few clean mornings here and there, but with barely any wave energy (hovering around 100 to 265), it's just not worth loading up the boards. The energy stays weak all the way through to the end of the forecast.
So, if you're keen, pencil in Thursday morning the 10th. Otherwise, it's a long wait for anything that grinds.
Rusty.
Short Range ForecastHeavy rain (total 152mm), heaviest during Sun afternoon. Warm (max 29°C on Wed morning, min 24°C on Sun afternoon). Winds decreasing (strong winds from the S on Mon morning, light winds from the SW by Tue morning). | Days 5-7 Weather SummaryModerate rain (total 12mm), heaviest on Wed night. Warm (max 28°C on Wed afternoon, min 21°C on Wed night). Winds decreasing (fresh winds from the SW on Wed afternoon, calm by Fri morning). | |||||||||||||||||||
Sun 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | ||||||||||||||
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 8 | ESE 8 | SSE 9 | S 9 | S 9 | S 9 | S 9 | S 9 | S 8 | S 9 | S 9 | S 8 | S 8 | ENE 6 | E 14 | E 14 | E 14 | E 14 | E 13 | E 13 |
Wave Graph  | ||||||||||||||||||||
 kJ | 892 | 975 | 1106 | 1689 | 1275 | 661 | 463 | 435 | 742 | 1088 | 471 | 163 | 104 | 73 | 106 | 101 | 136 | 134 | 130 | 130 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-off | off | cross-off | cross-off | cross-off | cross-on | cross-off | cross-off | cross-off | cross-off |
High Tide | 4:09PM1.19m | 10:16PM1.23m | 3:44PM1.25m | 00:42AM1.25m | 3:57PM1.30m | 2:06AM1.33m | 4:14PM1.34m | 3:06AM1.40m | 4:32PM1.36m | 3:56AM1.45m | 4:50PM1.39m | 4:41AM1.47m | 5:08PM1.41m | |||||||
Low Tide | 6:12PM1.19m | 7:30AM0.27m | 8:17PM1.09m | 8:30AM0.20m | 8:59PM0.95m | 9:17AM0.17m | 9:34PM0.80m | 9:55AM0.18m | 10:07PM0.64m | 10:29AM0.24m | 10:40PM0.50m | 10:59AM0.34m | 11:13PM0.38m | |||||||
 |  |  | | | |  | | | |  |  |  |  | | |  | | | | |
 | — | — | 5:13 | — | — | 5:15 | — | — | 5:16 | — | — | 5:16 | — | — | 5:16 | — | — | 5:18 | — | — |
 | 5:59 | — | — | 5:58 | — | — | 5:57 | — | — | 5:54 | — | — | 5:53 | — | — | 5:52 | — | — | 5:51 | — |
mm | 59 | 67 | 11 | 6 | 1 | 1 | — | 4 | 3 | 2 | 9 | 1 | — | — | — | — | — | — | — | — |
Temp °C | 24 | 26 | 27 | 27 | 27 | 28 | 28 | 27 | 29 | 28 | 24 | 22 | 22 | 24 | 25 | 25 | 23 | 24 | 24 | 23 |
Feels °C | 22 | 25 | 26 | 26 | 28 | 31 | 31 | 30 | 28 | 28 | 28 | 22 | 22 | 29 | 30 | 29 | 25 | 26 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | NE 13 | S 9 | E 8 | E 9 | S 9 | S 9 | S 9 | E 8 | E 9 | E 16 | S 9 | S 8 | S 8 | S 8 | S 7 | S 7 | E 14 | E 14 | E 13 | SE 9 |
| kJ | 27 | 130 | 291 | 290 | 961 | 661 | 463 | 32 | 24 | 21 | 471 | 163 | 104 | 55 | 39 | 39 | 136 | 134 | 130 | 64 |
Swell 2 Height (m) Direction Period (s) | SW 9 | S 9 | NE 8 | NE 11 | E 8 | E 8 | E 9 | SE 10 | NE 8 | NNE 8 | ESE 16 | ESE 15 | ESE 15 | ESE 14 | ENE 6 | E 14 | S 7 | ESE 9 | SE 9 | E 13 |
| kJ | 13 | 139 | 11 | 19 | 169 | 68 | 73 | 16 | 11 | 7 | 49 | 42 | 72 | 67 | 31 | 101 | 26 | 31 | 39 | 130 |
Swell 3 Height (m) Direction Period (s) | S 14 | NE 12 | ESE 11 | — | NE 11 | E 16 | SE 10 | NE 8 | E 17 | E 9 | E 9 | SE 11 | SE 9 | SE 9 | E 14 | SE 10 | ESE 9 | S 8 | SSW 7 | S 7 |
| kJ | 4 | 23 | 12 | — | 4 | 5 | 16 | 3 | 23 | 15 | 16 | 18 | 23 | 22 | 106 | 23 | 33 | 18 | 18 | 9 |
Wind waves Height (m) Direction Period (s) | E 8 | ESE 8 | SSE 9 | S 9 | S 9 | — | — | S 9 | S 8 | S 9 | NE 7 | NE 7 | NE 6 | ENE 6 | — | ENE 5 | NE 5 | NE 5 | NE 6 | NE 6 |
| kJ | 892 | 975 | 1106 | 1689 | 1275 | — | — | 435 | 742 | 1088 | 218 | 114 | 88 | 73 | — | 19 | 21 | 31 | 38 | 37 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 554 | 553 | 200 | 88 | 18 | 9 | 9 | 88 | 200 | 71 | 0 | 0 | 16 | 12 | 0 | 45 | 0 | 12 | 56 | 12 |
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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