Surf Forecasts:
Onjuku surf forecast from 19 Aug 2026:
- Best quality surf: Tuesday 25 Aug, 6AM (local time) - 11ft (3.5m), 16s period, SSE swell with onshore winds.
- Most powerful swell: Thursday 27 Aug, 12AM (local time) - 18ft (5.5m), 12s period, SSE swell with 9,148 kJ wave energy.
- Next surfable swell (1★+): Sunday 23 Aug, 12AM (local time) - 3.5ft (1.0m), 10s 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 Sunday (Aug 23) at 12AM. The primary swell is predicted to be 1.0m and 10s period with a secondary swell of 0.5m and 4s. 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 5.5m 12s and forecast to arrive on Thursday (Aug 27) at 12AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 5s period and expected on Sunday (Aug 23) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Sun 23rd Aug) | 3.5ft (1.0m) 10s |
| Best Surf | 6AM (Tue 25th Aug) | 11ft (3.5m) 16s |
| Most Powerful | 12AM (Thu 27th Aug) | 18ft (5.5m) 12s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
Short Range ForecastLight rain (total 3mm), mostly falling on Sat afternoon. Warm (max 28°C on Sat afternoon, min 24°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Sun night. Warm (max 28°C on Mon afternoon, min 24°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | |||||||||||||||
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) | SE 10 | SE 11 | SE 11 | S 9 | SE 10 | E 9 | E 11 | E 11 | E 10 | E 9 | SSE 14 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | S 15 | SSE 13 | SSE 12 | SSE 12 |
Wave Graph  | |||||||||||||||||||||
 kJ | 39 | 40 | 40 | 40 | 39 | 58 | 151 | 238 | 198 | 85 | 357 | 1692 | 2751 | 3428 | 4600 | 6043 | 6827 | 5270 | 4261 | 4554 | 9148 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | on | cross-on | on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross | on | on | cross-on | on | on | cross-on | cross-on | on |
High Tide | 9:58AM0.96m | 8:05PM1.32m | 8:35PM1.27m | 9:35PM1.21m | 4:31PM1.15m | 11:58PM1.18m | 4:19PM1.20m | 1:32AM1.23m | 4:27PM1.25m | 2:31AM1.30m | 4:41PM1.29m | ||||||||||
Low Tide | 1:21PM0.89m | 4:20AM0.49m | 6:00AM0.49m | 7:29AM0.43m | 7:50PM1.12m | 8:27AM0.35m | 8:48PM1.04m | 9:08AM0.28m | 9:22PM0.95m | 9:42AM0.22m | 9:51PM0.85m | ||||||||||
 | |  | | | | |  |  | | | | | |  | |  | |  | |  | |
 | 5:01 | — | — | 5:01 | — | — | 5:01 | — | — | 5:03 | — | — | 5:03 | — | — | 5:05 | — | — | 5:05 | — | — |
 | — | 6:22 | — | — | 6:21 | — | — | 6:19 | — | — | 6:17 | — | — | 6:16 | — | — | 6:15 | — | — | 6:14 | — |
mm | — | — | — | — | — | — | — | 1 | 2 | — | — | 1 | — | — | — | — | — | 1 | — | 1 | 6 |
Temp °C | 27 | 27 | 26 | 27 | 27 | 26 | 27 | 28 | 26 | 26 | 26 | 25 | 27 | 28 | 26 | 28 | 28 | 27 | 26 | 26 | 27 |
Feels °C | 29 | 29 | 29 | 29 | 28 | 28 | 28 | 30 | 30 | 29 | 29 | 29 | 30 | 30 | 28 | 31 | 30 | 31 | 29 | 27 | 29 |
Swell 1 Height (m) Direction Period (s) | SE 6 | E 8 | E 8 | E 8 | E 8 | E 9 | E 11 | E 11 | E 10 | E 9 | SSE 14 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | SSE 16 | S 15 | SSE 13 | E 12 | E 15 |
| kJ | 15 | 21 | 32 | 34 | 35 | 58 | 151 | 238 | 198 | 85 | 357 | 1692 | 2751 | 3428 | 4600 | 6043 | 6827 | 5270 | 4261 | 75 | 161 |
Swell 2 Height (m) Direction Period (s) | E 8 | SE 11 | SE 11 | S 9 | S 8 | S 9 | SSW 9 | SSW 9 | S 4 | SSE 14 | E 9 | ENE 9 | E 12 | ESE 12 | E 15 | E 14 | E 13 | E 13 | E 13 | ESE 16 | E 12 |
| kJ | 35 | 40 | 40 | 39 | 36 | 38 | 28 | 27 | 10 | 74 | 60 | 84 | 177 | 189 | 155 | 181 | 173 | 166 | 119 | 87 | 25 |
Swell 3 Height (m) Direction Period (s) | SE 10 | SSW 9 | SSW 8 | SE 11 | SE 10 | SE 10 | SE 10 | SE 10 | SSW 9 | SSW 9 | ESE 12 | ESE 12 | E 12 | SW 10 | E 14 | SW 10 | SW 10 | E 18 | E 18 | — | — |
| kJ | 39 | 16 | 13 | 40 | 39 | 35 | 25 | 28 | 26 | 15 | 56 | 49 | 220 | 36 | 107 | 16 | 16 | 27 | 54 | — | — |
Wind waves Height (m) Direction Period (s) | — | SE 5 | SE 5 | SSW 3 | S 3 | SSW 3 | S 5 | S 5 | — | NE 4 | NE 5 | — | — | SSW 8 | — | — | — | — | — | SSE 12 | SSE 12 |
| kJ | — | 10 | 6 | 2 | 5 | 4 | 23 | 21 | — | 19 | 35 | — | — | 12 | — | — | — | — | — | 4554 | 9148 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 9 | 9 | 17 | 9 | 17 | 23 | 17 | 0 | 0 | 0 | 0 | 9 | 9 | 18 | 18 | 1295 | 18 | 18 | 103 | 103 |
Best forecast wave conditions in Chiba | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Onjuku surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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.
Nearest