
Surf Forecasts:
Onjuku surf forecast from 7 Aug 2026:
- Best quality surf: Sunday 9 Aug, 3AM (local time) - 5.5ft (1.7m), 14s period, ESE swell with glassy winds.
- Most powerful swell: Monday 10 Aug, 9PM (local time) - 8ft (2.4m), 11s period, ENE swell with 1,322 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 2.4m 11s and forecast to arrive on Monday (Aug 10) 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 1.0m 5s period and expected on Monday (Aug 10) at 12PM.
| 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 (Sun 9th Aug) | 5.5ft (1.7m) 14s |
| Most Powerful | 9PM (Mon 10th Aug) | 8ft (2.4m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it. We’re looking at a 16-day window for Onjuku, and honestly, it’s a bit of a mixed bag. We’ve got a long stretch of nothing special to wade through before we see a couple of glimpses of proper surf. The water is sitting at 78°F right now, which is a bit colder than normal for this time of year, so you might want a slightly warmer suit.
The first recommendation isn’t until Sunday the 9th. Before that, Saturday the 8th is a write-off with light cross-onshore winds messing up small, marginal waves. So, we’ve got a day of waiting.
Sunday the 9th is the real standout in the first week. The morning session is where it’s at. Onjuku is picking up a solid ESE groundswell at 6ft, with a long 13-second period. The wind is a light cross-offshore from the NE, which is going to leave the surface looking clean. The combined energy is pumping at (1131), so there’s plenty of push. This is a good one for experienced surfers, as the size is getting up there. It’s a bit inconsistent though, so you’ll have to be patient for the sets.
From Monday the 10th through to the morning of Wednesday the 20th, it’s a long stretch of mostly marginal conditions. The swell sticks around, but the winds are either too strong or from the wrong direction, making things choppy or just messy. There’s a period mid-week where it’s just poor, with thunderstorms and cross-onshore winds killing the vibe. The 19th looks a bit rough with a raw cross-shore wind.
Then we finally get back on track. Thursday the 20th morning is the second standout. The swell drops a touch to 6ft, coming from the S with a 10-second period, but the magic is in the wind. A light cross-offshore breeze from the E will have the waves looking super clean. The energy is solid at (839) and the forecast says “very good surf conditions.” This is the one to circle on the calendar for a decent session with smaller crowds likely.
After that, the surf fades out quickly into the weekend of the 22nd, with tiny, weak swell and onshore winds. The very end of the forecast on Sunday the 23rd shows a promising pulse of SE groundswell with a 12 to 13-second period and offshore winds, but that’s a long way out and the wind is looking strong. Keep an eye on it, but don’t plan your life around it just yet.
So, bottom line: Sunday the 9th morning is the best early call – get on it if you’re experienced. The 20th morning is your next best bet for clean, fun waves. The rest is a waiting game.
Rusty, out.
Short Range ForecastMostly dry. Warm (max 28°C on Sat morning, min 22°C on Mon night). Winds increasing (calm on Sat night, fresh winds from the NE by Mon morning). | Days 4-6 Weather SummaryHeavy rain (total 28mm), heaviest during Thu night. Warm (max 27°C on Tue afternoon, min 25°C on Tue morning). Winds decreasing (fresh winds from the SSW on Tue afternoon, light winds from the E by Wed night). | ||||||||||||||||||||
Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | |||||||||||||||
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 11 | ESE 13 | ESE 14 | ESE 13 | ESE 13 | ESE 12 | E 12 | E 11 | E 11 | E 11 | E 10 | E 10 | E 9 | E 9 | E 10 | E 11 | E 10 | E 11 | E 9 | E 9 | E 11 |
Wave Graph | |||||||||||||||||||||
350 | 624 | 1053 | 998 | 938 | 781 | 997 | 951 | 819 | 730 | 543 | 392 | 202 | 189 | 234 | 657 | 426 | 564 | 896 | 766 | 875 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | on | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-off | cross-off | cross | cross-off | cross-off | cross-off |
High Tide | 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 | 4:40AM1.50m | 6:04PM1.38m | |||||||||
Low Tide | 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 | 11:29AM0.11m | 11:38PM0.63m | |||||||||
4:52 | — | — | 4:52 | — | — | 4:52 | — | — | 4:54 | — | — | 4:54 | — | — | 4:56 | — | — | 4:56 | — | — | |
— | 6:36 | — | — | 6:35 | — | — | 6:32 | — | — | 6:31 | — | — | 6:30 | — | — | 6:30 | — | — | 6:29 | — | |
mm | — | — | — | — | — | — | — | — | — | — | 1 | 1 | 3 | 3 | 8 | 1 | 1 | 10 | 2 | 4 | 13 |
Temp °C | 28 | 27 | 25 | 27 | 27 | 24 | 26 | 25 | 24 | 26 | 27 | 27 | 27 | 27 | 26 | 27 | 27 | 26 | 28 | 27 | 26 |
Feels °C | 30 | 28 | 28 | 28 | 28 | 26 | 24 | 22 | 24 | 25 | 26 | 26 | 28 | 28 | 29 | 28 | 28 | 29 | 30 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | S 11 | ESE 13 | ESE 14 | ESE 13 | ESE 13 | ESE 12 | E 12 | E 11 | E 11 | E 11 | E 10 | E 10 | E 9 | E 9 | E 10 | E 10 | E 10 | E 11 | S 9 | S 9 | E 11 |
350 | 624 | 1053 | 998 | 938 | 781 | 997 | 951 | 819 | 730 | 543 | 392 | 202 | 189 | 234 | 470 | 426 | 564 | 44 | 45 | 875 | |
Swell 2 Height (m) Direction Period (s) | ESE 9 | S 11 | S 11 | S 10 | S 10 | S 10 | S 11 | SSW 11 | S 10 | S 11 | S 11 | S 10 | S 10 | S 10 | S 10 | S 10 | S 10 | S 10 | SSE 11 | SSE 11 | SSE 10 |
236 | 282 | 231 | 133 | 106 | 102 | 85 | 100 | 77 | 82 | 85 | 77 | 77 | 106 | 80 | 74 | 73 | 49 | 12 | 23 | 39 | |
Swell 3 Height (m) Direction Period (s) | E 14 | E 10 | SW 14 | — | SW 12 | SW 12 | SW 12 | SE 14 | SW 12 | SSW 10 | SSW 11 | SSW 10 | SE 4 | SSE 12 | SE 12 | SE 12 | SSE 11 | SSE 11 | SE 16 | SE 15 | SSW 9 |
36 | 46 | 29 | — | 84 | 38 | 38 | 8 | 21 | 115 | 128 | 146 | 8 | 14 | 21 | 5 | 13 | 24 | 10 | 9 | 28 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | SE 4 | ESE 4 | — | NNE 8 | E 11 | — | — | E 9 | E 9 | — |
— | — | — | — | — | — | — | — | — | — | — | 10 | 8 | — | 33 | 657 | — | — | 896 | 766 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 103 | 9 | 0 | 103 | 0 | 56 | 56 | 22 | 18 | 200 | 9 | 51 | 103 | 9 | 15 | 51 | 51 | 51 | 103 | 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.











