Surf Forecasts:
Onjuku surf forecast from 27 Jul 2026:
- Best quality surf: Tuesday 4 Aug, 6AM (local time) - 11ft (3.5m), 18s period, SE swell with offshore winds.
- Most powerful swell: Tuesday 4 Aug, 9AM (local time) - 11ft (3.5m), 18s period, SE swell with 8,107 kJ wave energy.
- Next surfable swell (1★+): Tuesday 28 Jul, 6AM (local time) - 3.5ft (1.0m), 8s period with ENE 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 Tuesday (Jul 28) at 6AM. The primary swell is predicted to be 1.0m and 8s period with a secondary swell of 0.5m and 10s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 3.5m 18s and forecast to arrive on Tuesday (Aug 04) 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 Tuesday (Aug 04) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Tue 28th Jul) | 3.5ft (1.0m) 8s |
| Best Surf | 6AM (Tue 4th Aug) | 11ft (3.5m) 18s |
| Most Powerful | 9AM (Tue 4th Aug) | 11ft (3.5m) 18s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright, I’m looking at the forecast for Onjuku here, and I gotta be straight with you – the first week is a bit of a struggle. The surf is small and the conditions are just ordinary. We’ve got a run of days from July 28th right through August 1st where the swell is tiny, mostly under 3 feet, and the wind is all over the place. The morning of the 29th is a standout early on, with a glassy, clean 3ft SSW swell, but the waves are weak and inconsistent. The energy is low (113), so it’s a bit of a pokey wave for a longboard or a foamie. The water temp is about average for the time of year.
Then the real action starts to build. From August 2nd, the swell starts to pick up, and by August 4th, we’re looking at a serious pulse of long-period groundswell from the SE. The morning of the 4th is the best on offer. The swell is 10ft, with a period of 18 seconds, and the wind is a clean cross-offshore from the NE. The energy is massive (6061), and the waves should be powerful and lined up. This is a standout session for experienced surfers, but it’s going to be well overhead. This is not a beginner wave. August 5th is even bigger, with 18ft swell, but that’s getting into serious territory – only for the experts. The wind stays favorable, but the swell is too big for the average punter.
August 6th is still huge, but the wind shifts to a cross-shore and then a cross-onshore, making it messy. The quality drops off fast after that. From August 7th to the 8th, the swell is still big, but the wind is onshore and choppy, so it’s a write-off. You’ll see some cleanup on the 9th and 10th of August, with the swell dropping back to a more manageable 4ft to 5ft, but the wind is still cross or cross-off, so it’s not perfect. The morning of August 11th has a clean 4ft swell from the ESE with a period of 11 seconds, and the energy is moderate (455). It’s a better option, but it’s not the same as that big clean pulse we saw earlier.
So, to sum it up: the first week is a flat, slow grind. The real standout is the morning of August 4th, with that big, clean, long-period swell. The morning of August 11th is a decent second option for a smaller, cleaner session. The second week is a bit of a mixed bag with some decent swell, but the wind is always a factor.
Rusty
Short Range ForecastLight rain (total 5mm), mostly falling on Tue night. Warm (max 28°C on Wed morning, min 24°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 4mm), mostly falling on Fri night. Warm (max 29°C on Fri morning, min 24°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 28 | Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | |||||||||||||||
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) | ENE 8 | ENE 8 | ENE 8 | SW 7 | SW 7 | SSW 7 | SSW 7 | SE 9 | SE 9 | SE 9 | ENE 8 | SE 9 | SE 15 | SE 14 | SE 14 | SE 14 | SE 15 | SE 15 | SE 16 | SE 16 | SE 17 |
Wave Graph  | |||||||||||||||||||||
 kJ | 81 | 58 | 45 | 244 | 200 | 59 | 42 | 31 | 22 | 30 | 22 | 31 | 58 | 71 | 164 | 373 | 535 | 1135 | 2415 | 3048 | 4935 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | on | cross | glassy | cross-on | off | cross | on | glassy | off | cross | cross-off | cross-off | cross | cross-on | cross-on | cross-on | cross | cross-off | cross-off | cross-off |
High Tide | 5:21PM1.27m | 3:19AM1.38m | 5:42PM1.30m | 4:01AM1.42m | 6:03PM1.32m | 4:41AM1.43m | 6:23PM1.34m | 5:20AM1.41m | 6:44PM1.36m | 6:00AM1.37m | 7:05PM1.38m | 6:43AM1.30m | 7:27PM1.38m | ||||||||
Low Tide | 10:04AM0.17m | 10:04PM0.97m | 10:37AM0.13m | 10:38PM0.90m | 11:08AM0.12m | 11:11PM0.83m | 11:38AM0.14m | 11:45PM0.75m | 12:06PM0.20m | 00:21AM0.68m | 12:33PM0.28m | 00:59AM0.61m | 1:00PM0.40m | 1:40AM0.55m | |||||||
 | |  |  |  | | | |  | | | |  | |  | | |  | | | | |
 | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — | 4:46 | — | — | 4:46 | — | — | 4:47 | — | — | 4:48 | — | — |
 | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — |
mm | — | — | 2 | — | 1 | 2 | — | — | — | — | — | 3 | 1 | — | — | — | — | — | — | — | — |
Temp °C | 26 | 27 | 27 | 28 | 28 | 26 | 28 | 28 | 26 | 29 | 28 | 26 | 25 | 26 | 25 | 27 | 26 | 25 | 26 | 26 | 24 |
Feels °C | 29 | 29 | 28 | 32 | 31 | 30 | 31 | 31 | 30 | 32 | 31 | 29 | 27 | 28 | 28 | 30 | 28 | 27 | 26 | 26 | 25 |
Swell 1 Height (m) Direction Period (s) | ENE 8 | ENE 8 | ENE 8 | SSW 7 | SSW 7 | SSW 7 | SSW 7 | S 7 | SSE 6 | ENE 8 | ENE 8 | ENE 7 | NE 7 | ESE 10 | SE 14 | SE 14 | SE 15 | SE 15 | SE 16 | SE 16 | SE 17 |
| kJ | 81 | 58 | 45 | 82 | 89 | 59 | 42 | 27 | 12 | 22 | 22 | 21 | 19 | 52 | 164 | 373 | 535 | 1135 | 2415 | 3048 | 4935 |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 10 | SE 10 | SE 10 | SE 10 | SE 10 | SE 10 | ENE 8 | NE 7 | SE 9 | SSW 7 | S 6 | ESE 11 | SE 14 | ENE 7 | NE 7 | ENE 7 | E 14 | E 14 | E 14 | E 14 |
| kJ | 49 | 35 | 35 | 45 | 33 | 23 | 32 | 22 | 14 | 30 | 18 | 12 | 38 | 71 | 33 | 25 | 18 | 65 | 61 | 61 | 58 |
Swell 3 Height (m) Direction Period (s) | SSW 8 | SSW 8 | SSW 8 | ENE 6 | ENE 6 | E 9 | NE 7 | SE 9 | SE 9 | SW 7 | SE 9 | SE 9 | SE 15 | SSW 7 | ESE 10 | E 15 | ESE 9 | — | — | — | — |
| kJ | 24 | 24 | 14 | 13 | 7 | 14 | 12 | 31 | 22 | 13 | 14 | 31 | 58 | 9 | 56 | 41 | 31 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | SSE 3 | SSW 5 | SW 7 | SW 7 | — | ENE 3 | — | — | — | ENE 3 | ENE 3 | ENE 4 | ENE 7 | — | — | NE 7 | ENE 7 | NE 4 | ENE 5 | NE 6 |
| kJ | — | 1 | 25 | 244 | 200 | — | 2 | — | — | — | 2 | 1 | 10 | 41 | — | — | 38 | 17 | 17 | 40 | 142 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 9 | 15 | 0 | 9 | 0 | 9 | 9 | 0 | 0 | 554 | 0 | 2464 | 9 | 9 | 9 | 9 | 51 | 51 | 51 | 40 |
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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