Surf Forecasts:
Onjuku surf forecast from 24 Jul 2026:
- Best quality surf: Thursday 30 Jul, 12AM (local time) - 5.5ft (1.7m), 8s period, NE swell with offshore winds.
- Most powerful swell: Thursday 30 Jul, 12AM (local time) - 5.5ft (1.7m), 8s period, NE swell with 362 kJ wave energy.
- Next surfable swell (1★+): Saturday 25 Jul, 6AM (local time) - 1.5ft (0.5m), 10s period with SE 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 Saturday (Jul 25) at 6AM. The primary swell is predicted to be 0.5m and 10s period with a secondary swell of 0.6m and 4s. Another secondary swell of 0.5m and 8s is also forecast. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 1.7m 8s and forecast to arrive on Thursday (Jul 30) at 12AM. Winds are predicted to be 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 Wednesday (Jul 29) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Sat 25th Jul) | 1.5ft (0.5m) 10s |
| Best Surf | 12AM (Thu 30th Jul) | 5.5ft (1.7m) 8s |
| Most Powerful | 12AM (Thu 30th Jul) | 5.5ft (1.7m) 8s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright, Rusty here again, but this time in feet and miles. Let’s break down Onjuku.
For the first week and a half, it’s a real struggle to find anything worth paddling out for. The first decent-looking slot comes on Tuesday, July 28th. That morning, we’ve got a 3ft swell from the east, with a period of 8 seconds and a light cross-offshore breeze from the east-northeast at 6 mph. The water is sitting at a comfortable 79°, which is right about average for the time of year, nothing wild. The wave energy is moderate (214), and the conditions look clean. It’s not a day to write home about, but it’s the first honest chance after a long, quiet stretch.
The real action, though, kicks off in early August. From Wednesday, August 5th, things get serious. The morning of the 5th shows a 8ft swell from the south-southeast, with a very long period of 16 seconds and a fresh cross-offshore breeze from the north-northeast at 18 mph. The wave energy is very strong (2962). By the afternoon, we’re looking at 8ft from the same direction, a 17-second period, and energy jumping to 4064. The wind stays clean, but the swell is pushing past 8ft, so this is experts-only territory.
The peak hits on Thursday, August 6th. The morning brings an 12ft SSE swell, 17-second period, and a fresh north-northeast cross-offshore at 21 mph. The energy is massive (6535). The afternoon gets even bigger: 13ft, 17 seconds, and 25 mph winds from the northeast. The wind and tide are favorable, but the swell is too big for this break. For a paddler, it’s a beast. For a kiteboarder, that’s prime time.
Friday, August 7th, and Saturday, August 8th, are huge: 16ft to 20ft swells with very long periods (18 seconds) and strong offshore winds gusting up to 31 mph. The wave energy is astronomical (over 15,000 and then over 21,000). The wind is offshore, but by Saturday it’s near gale-force, making paddling out nearly impossible. This is massive, powerful, and dangerous. Only the most experienced should even look at it.
So, the standout is the window from Wednesday, August 5th, to Saturday, August 8th. It’s a massive, long-period groundswell with clean offshore winds, but it’s just plain big. If you’re an expert, the morning of Thursday, August 6th, is your best call before the wind gets too strong. For everyone else, the first week is a dud, and then it’s too big. Onjuku is an inconsistent spot, so a long quiet run like this is pretty normal for the area.
Rusty.
Short Range ForecastHeavy rain (total 43mm), heaviest during Sun night. Warm (max 28°C on Fri afternoon, min 22°C on Sun night). Winds increasing (calm on Fri night, fresh winds from the NNE by Sun night). | Days 5-7 Weather SummaryMostly dry. Warm (max 26°C on Tue morning, min 23°C on Mon night). Wind will be generally light. | |||||||||||||||||||
Fri 24 | Saturday 25 | Sunday 26 | Monday 27 | Tuesday 28 | Wednesday 29 | Thursday 30 | ||||||||||||||
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 11 | SE 16 | SE 10 | SE 16 | SE 15 | SE 15 | SE 15 | SE 10 | NE 8 | NE 7 | ENE 8 | E 8 | E 8 | NE 9 | SE 10 | NE 6 | NE 8 | ENE 8 | ENE 8 | ENE 8 |
Wave Graph  | ||||||||||||||||||||
 kJ | 57 | 66 | 48 | 63 | 57 | 55 | 64 | 72 | 160 | 156 | 107 | 114 | 117 | 172 | 33 | 139 | 362 | 159 | 137 | 77 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-off | cross-off | off | cross-off | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-on | glassy | cross-off | cross-off | off | glassy | on | cross-on |
High Tide | 11:05PM1.26m | 4:30PM1.13m | 00:24AM1.25m | 4:42PM1.19m | 1:35AM1.28m | 5:00PM1.23m | 2:32AM1.33m | 5:21PM1.27m | 3:19AM1.38m | 5:42PM1.30m | 4:01AM1.42m | 6:03PM1.32m | ||||||||
Low Tide | 7:51AM0.37m | 7:16PM1.10m | 8:43AM0.30m | 8:40PM1.07m | 9:26AM0.23m | 9:28PM1.02m | 10:04AM0.17m | 10:04PM0.97m | 10:37AM0.13m | 10:38PM0.90m | 11:08AM0.12m | 11:11PM0.83m | ||||||||
 |  |  |  | | | | |  | |  |  | |  | | |  | | | | |
 | — | — | 4:41 | — | — | 4:41 | — | — | 4:43 | — | — | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — |
 | 6:47 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — |
mm | — | 3 | 2 | — | 8 | 1 | 1 | 26 | 2 | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 28 | 27 | 28 | 27 | 24 | 25 | 26 | 25 | 25 | 25 | 24 | 26 | 26 | 25 | 25 | 25 | 23 | 26 | 27 | 26 |
Feels °C | 32 | 32 | 33 | 30 | 25 | 28 | 29 | 29 | 24 | 24 | 26 | 28 | 28 | 27 | 26 | 26 | 25 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | E 9 | E 9 | E 8 | SE 10 | SE 10 | ENE 6 | E 6 | ENE 7 | SE 10 | SE 10 | ENE 8 | SE 10 | SE 10 | ENE 8 | SE 10 | SE 10 | ENE 8 | ENE 8 | ENE 8 | ENE 8 |
| kJ | 39 | 36 | 35 | 49 | 50 | 18 | 24 | 38 | 51 | 61 | 107 | 49 | 35 | 122 | 33 | 32 | 257 | 159 | 137 | 77 |
Swell 2 Height (m) Direction Period (s) | SE 11 | SE 10 | SE 10 | E 8 | E 8 | SE 10 | SE 10 | SE 10 | SE 14 | SSW 8 | SE 10 | SSW 8 | SSW 8 | SE 10 | S 6 | SSW 6 | SE 9 | SE 9 | SE 10 | SE 10 |
| kJ | 57 | 51 | 48 | 34 | 21 | 53 | 64 | 64 | 51 | 22 | 63 | 24 | 14 | 35 | 11 | 8 | 31 | 31 | 23 | 24 |
Swell 3 Height (m) Direction Period (s) | SE 17 | SE 16 | SE 4 | SE 16 | SE 15 | SE 15 | SE 15 | SE 14 | S 8 | SE 14 | SSW 8 | SE 13 | SE 13 | S 5 | SE 13 | SE 12 | SSW 8 | SSW 7 | SSW 7 | SSW 7 |
| kJ | 43 | 66 | 5 | 63 | 57 | 55 | 54 | 72 | 13 | 47 | 22 | 27 | 27 | 8 | 25 | 23 | 13 | 11 | 10 | 5 |
Wind waves Height (m) Direction Period (s) | E 3 | SE 4 | — | SE 4 | ENE 4 | NNE 5 | — | NE 2 | NE 8 | NE 7 | — | E 8 | E 8 | NE 9 | NE 6 | NE 6 | NE 8 | — | — | — |
| kJ | 2 | 8 | — | 4 | 8 | 11 | — | 1 | 160 | 156 | — | 114 | 117 | 172 | 101 | 139 | 362 | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 9 | 9 | 0 | 56 | 0 | 0 | 9 | 9 | 553 | 51 | 0 | 0 | 9 | 0 | 12 | 56 | 0 | 0 | 9 | 18 |
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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