
Surf Forecasts:
Onjuku surf forecast from 28 Jul 2026:
- Best quality surf: Tuesday 4 Aug, 6AM (local time) - 11ft (3.5m), 17s period, SE swell with offshore winds.
- Most powerful swell: Wednesday 5 Aug, 3AM (local time) - 16ft (5.0m), 17s period, SE swell with 13,973 kJ wave energy.
- Next surfable swell (1★+): Thursday 30 Jul, 12AM (local time) - 2.5ft (0.8m), 7s period with SSW 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 30) at 12AM. The primary swell is predicted to be 0.8m and 7s period with a secondary swell of 0.4m and 10s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 5.0m 17s and forecast to arrive on Wednesday (Aug 05) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 6s period and expected on Tuesday (Aug 04) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Thu 30th Jul) | 2.5ft (0.8m) 7s |
| Best Surf | 6AM (Tue 4th Aug) | 11ft (3.5m) 17s |
| Most Powerful | 3AM (Wed 5th Aug) | 16ft (5.0m) 17s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright, Rusty here. Let's talk about Onjuku.
First up, the water temp is sitting pretty much average for this time of year, nothing wild to report.
Alright, the outlook starts off pretty flat. Wednesday the 29th has some swell, but it's messy. Thursday morning, the 30th, is the first real chance to get wet. The swell is tiny, only 2ft from the south, but the wind is glassy. That means it'll be clean, but you'll be hunting for knee-high bumps. The wave energy is low (91). It's a mellow start.
Things stay small and ordinary through Friday and into Saturday, with clean conditions but barely any power. The energy is in the double digits, just weak stuff.
Then, here's the good news. We get a real pulse on Sunday, August 2nd. The morning looks the pick of the whole forecast. We're looking at a clean 4ft swell from the southeast, but the period is a very long 15 seconds. That's proper groundswell. The energy jumps to 608 (moderate), and with light offshore winds, the waves will be lined up and clean. This is the standout session. The long period will mean better shaped waves but longer waits between sets. For a beach break like Onjuku, it could break a little straight, but it's still the best on offer.
Monday, August 3rd, sees the swell pump up. Morning brings 7ft from the southeast with a very long 17-second period, and the wind is clean offshore. The energy is strong (2856). This is getting big. By the afternoon, it's 8ft with the same long period and strong energy (4198). This is solid expert territory, getting too big for most.
Tuesday, August 4th, the swell is too big for Onjuku. Morning is 12ft, afternoon is 13ft, all from the southeast with very long period. The energy is huge (6833 and 8365). This is for big-wave specialists only. The same goes for Wednesday, August 5th, with 18ft surf and massive energy (17673 and 18456). The wind stays cross-offshore, but the size is just overwhelming for this break.
From Thursday, August 6th, through to the end of the forecast on Thursday, August 13th, the conditions turn poor. The wind shifts onshore and the swell, while still big at times, gets chopped up and messy. It's a write-off for quality surfing.
So, the clear winner is Sunday morning, August 2nd. Get on it for the cleanest, most fun waves of the period. The weekend that follows is for the brave and the very experienced only.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Tue night. Warm (max 30°C on Wed afternoon, min 25°C on Tue night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 7mm), mostly falling on Fri night. Warm (max 26°C on Sat afternoon, min 23°C on Fri night). Wind will be generally light. | ||||||||||||||||||
Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | ||||||||||||||
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) | SSW 5 | SSW 7 | SSW 7 | SSW 7 | S 7 | S 7 | S 7 | SSW 7 | SSW 7 | ENE 8 | ENE 8 | SE 10 | SE 16 | SE 15 | SE 14 | SE 16 | SE 17 | SE 18 | SE 18 |
Wave Graph | |||||||||||||||||||
64 | 266 | 114 | 59 | 47 | 39 | 36 | 52 | 26 | 40 | 37 | 50 | 127 | 551 | 536 | 1179 | 2748 | 4137 | 5579 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross-on | glassy | glassy | cross-on | on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 10:04PM0.97m | 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 | — | — | 4:45 | — | — | 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 | — | — | 1 | 6 | 1 | — | — | — | — | — | — | — | — |
Temp °C | 27 | 29 | 30 | 27 | 29 | 29 | 28 | 26 | 27 | 24 | 24 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 24 |
Feels °C | 27 | 31 | 32 | 30 | 34 | 32 | 31 | 28 | 30 | 27 | 26 | 28 | 28 | 28 | 27 | 27 | 25 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | SSW 5 | SSW 7 | SE 10 | SSW 7 | S 7 | SE 9 | S 7 | SSW 7 | SSW 7 | S 6 | SE 11 | SE 10 | SE 10 | SE 15 | SE 14 | SE 16 | SE 17 | SE 18 | SE 18 |
35 | 105 | 33 | 59 | 47 | 31 | 36 | 52 | 26 | 13 | 29 | 50 | 102 | 551 | 536 | 1179 | 2748 | 4137 | 5579 | |
Swell 2 Height (m) Direction Period (s) | ENE 8 | SE 10 | E 9 | SE 10 | SE 10 | E 8 | SE 9 | SE 9 | SE 9 | SE 9 | S 5 | NE 7 | SE 16 | NE 7 | ESE 9 | E 15 | E 14 | E 14 | E 14 |
45 | 45 | 25 | 23 | 32 | 12 | 22 | 30 | 14 | 31 | 5 | 14 | 127 | 14 | 70 | 67 | 61 | 61 | 132 | |
Swell 3 Height (m) Direction Period (s) | SE 10 | NE 8 | NE 9 | E 9 | E 8 | E 3 | ENE 8 | ENE 8 | NE 8 | E 11 | ESE 11 | ESE 11 | NE 7 | E 16 | E 15 | NE 7 | — | — | — |
35 | 11 | 12 | 14 | 12 | 1 | 13 | 12 | 14 | 20 | 22 | 39 | 27 | 43 | 68 | 14 | — | — | — | |
Wind waves Height (m) Direction Period (s) | SSW 5 | SSW 7 | SSW 7 | — | — | S 7 | — | NE 4 | NE 3 | ENE 8 | ENE 8 | E 4 | ENE 8 | — | NE 8 | ENE 7 | ENE 7 | NE 4 | — |
64 | 266 | 114 | — | — | 39 | — | 6 | 6 | 40 | 37 | 9 | 58 | — | 28 | 37 | 47 | 18 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 9 | 2 | 9 | 0 | 0 | 2 | 9 | 12 | 0 | 71 | 0 | 0 | 0 | 0 | 51 | 0 | 51 | 68 | 51 |
Best forecast wave conditions in Chiba | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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.










