Surf Forecasts:
Onjuku surf forecast from 17 Jul 2026:
- Best quality surf: Thursday 23 Jul, 3AM (local time) - 2.5ft (0.8m), 10s period, E swell with offshore winds.
- Most powerful swell: Tuesday 21 Jul, 12AM (local time) - 3.5ft (1.1m), 11s period, E swell with 272 kJ wave energy.
- Next surfable swell (1★+): Thursday 23 Jul, 3AM (local time) - 2.5ft (0.8m), 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 Thursday (Jul 23) at 3AM. The primary swell is predicted to be 0.8m and 10s period with a secondary swell of 0.3m and 4s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 1.1m 11s and forecast to arrive on Tuesday (Jul 21) at 12AM. 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 Thursday (Jul 23) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Thu 23rd Jul) | 2.5ft (0.8m) 10s |
| Best Surf | 3AM (Thu 23rd Jul) | 2.5ft (0.8m) 10s |
| Most Powerful | 12AM (Tue 21st Jul) | 3.5ft (1.1m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
G’day, Rusty here, with the local run-down. The first week’s a dud—tiny, choppy, and not worth paddling out for. From Saturday 18 July to Friday 24 July morning, swell is 2 to 3 feet at best, with onshore or cross-onshore winds out of the south and southwest. The wave energy is weak to moderate (73 to 317), so there’s nothing to get excited about. Thursday 23 July and Friday 24 July morning see a light NE breeze cleaning up the 2-foot E swell, making it surfable but very ordinary.
Then it goes flat again until the real action starts. From Monday 27 July, the swell builds. Monday afternoon brings a 6-foot SSE swell with a 12-second period, energy at 1124—strong. The wind is onshore, so it’s messy, but the power is there.
The standout is Onjuku (Japan). Tuesday 28 July offers a 7-foot SSE swell, 12 to 13 seconds, energy at 1311 to 2237—very strong. The wind is cross-on, so it’s a bit bumpy, but at 7 feet it’s expert-only territory. The swell direction (SSE) matches the optimum, so the break is dialed in.
The best of the run is Wednesday 29 July morning: a 10-foot SSE swell, 14-second period, energy at 3354—very strong. The wind is light SE cross-on, so it’s glassy and clean. That’s big, powerful surf for the experienced crew only. The afternoon drops to 8 feet but still pumps.
Thursday 30 July and Friday 31 July keep the swell at 7 feet from the south, with a very long 14-second period. Thursday has a cross-off wind, but Friday is the real winner: a 30 km/h offshore from the NNW in the morning, then a gentle offshore in the afternoon. That 7-foot S groundswell with clean offshore wind is excellent for experienced surfers.
After that, Saturday 1 August and Sunday 2 August drop back to messy, choppy conditions with swell fading from 6 feet to 3 feet.
So, beginners, stay out of the water from the 27 July onward. For the rest, the absolute pick is Friday 31 July afternoon at Onjuku—clean, offshore, 7-foot S groundswell. The Wednesday 29 July morning is also a standout for the sheer size. The break is inconsistent, so patience is key, but the quality is there.
Rusty.
Short Range ForecastMostly dry. Warm (max 28°C on Mon morning, min 25°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Wed night. Warm (max 29°C on Tue morning, min 25°C on Wed night). Wind will be generally light. | ||||||||||||||||||||
Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | |||||||||||||||
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) | E 8 | ESE 9 | ESE 9 | ESE 9 | E 9 | E 9 | E 9 | E 8 | E 11 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 9 | E 9 | E 9 | E 9 | SE 11 | SE 16 |
Wave Graph  | |||||||||||||||||||||
 kJ | 116 | 173 | 185 | 232 | 165 | 127 | 119 | 116 | 272 | 257 | 247 | 196 | 156 | 153 | 118 | 85 | 81 | 58 | 56 | 57 | 66 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | on | on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross | cross-off |
High Tide | 7:45PM1.33m | 7:06AM1.30m | 8:08PM1.33m | 8:01AM1.17m | 8:32PM1.33m | 9:07AM1.04m | 8:57PM1.32m | 10:41AM0.95m | 9:26PM1.31m | 10:06PM1.28m | 11:05PM1.26m | ||||||||||
Low Tide | 1:04PM0.23m | 1:26AM0.69m | 1:34PM0.40m | 2:16AM0.63m | 2:01PM0.57m | 3:11AM0.58m | 2:24PM0.72m | 4:14AM0.54m | 2:41PM0.85m | 5:28AM0.50m | 6:45AM0.44m | ||||||||||
 | |  | |  | | | | | | | | |  |  | | |  | | | | |
 | 4:35 | — | — | 4:37 | — | — | 4:37 | — | — | 4:37 | — | — | 4:39 | — | — | 4:39 | — | — | 4:39 | — | — |
 | — | 6:52 | — | — | 6:51 | — | — | 6:51 | — | — | 6:50 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 4 | — | — | — | — | — | — |
Temp °C | 27 | 27 | 25 | 27 | 27 | 26 | 28 | 28 | 26 | 29 | 29 | 27 | 29 | 29 | 27 | 27 | 27 | 26 | 27 | 28 | 26 |
Feels °C | 29 | 29 | 28 | 29 | 29 | 29 | 31 | 29 | 28 | 31 | 30 | 31 | 34 | 31 | 30 | 29 | 30 | 30 | 30 | 32 | 31 |
Swell 1 Height (m) Direction Period (s) | E 8 | ESE 9 | ESE 9 | ESE 9 | E 9 | E 9 | E 9 | E 8 | E 11 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 9 | E 9 | E 9 | E 9 | E 9 | E 9 |
| kJ | 116 | 173 | 185 | 232 | 165 | 127 | 119 | 116 | 272 | 257 | 247 | 196 | 156 | 153 | 118 | 85 | 81 | 58 | 56 | 56 | 36 |
Swell 2 Height (m) Direction Period (s) | SSE 9 | SE 8 | S 8 | S 8 | S 8 | SSE 7 | S 7 | E 13 | SSE 8 | SSE 8 | SSE 8 | SSE 8 | SSW 4 | SSE 7 | SSW 4 | SE 10 | SE 10 | SE 10 | SE 9 | SE 11 | SE 10 |
| kJ | 54 | 34 | 5 | 10 | 11 | 29 | 4 | 50 | 13 | 6 | 6 | 6 | 6 | 5 | 6 | 25 | 16 | 24 | 22 | 57 | 52 |
Swell 3 Height (m) Direction Period (s) | SW 7 | S 9 | SE 13 | SE 12 | SE 12 | S 8 | SSE 9 | SSE 7 | S 7 | S 7 | SE 11 | ESE 11 | SSE 7 | SSE 11 | SSE 10 | SSW 6 | SSW 5 | SE 18 | SE 18 | SE 16 | SE 16 |
| kJ | 2 | 2 | 6 | 6 | 6 | 5 | 8 | 5 | 1 | 1 | 19 | 12 | 5 | 12 | 11 | 6 | 5 | 49 | 49 | 43 | 66 |
Wind waves Height (m) Direction Period (s) | SSE 4 | — | SSE 7 | SSE 8 | SSE 4 | — | S 7 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | — | NE 4 | ENE 4 | E 4 | E 4 | ESE 4 | ESE 4 |
| kJ | 6 | — | 21 | 54 | 10 | — | 24 | 22 | 15 | 13 | 28 | 10 | 13 | 5 | — | 19 | 18 | 19 | 9 | 10 | 11 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 17 | 23 | 17 | 598 | 17 | 9 | 9 | 2 | 0 | 0 | 0 | 0 | 9 |
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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