Surf Forecasts:
Onjuku surf forecast from 30 Aug 2026:
- Best quality surf: Tuesday 1 Sep, 6AM (local time) - 3ft (0.9m), 12s period, ESE swell with cross-offshore winds.
- Most powerful swell: Monday 7 Sep, 9AM (local time) - 6ft (1.8m), 13s period, SSE swell with 1,044 kJ wave energy.
- Next surfable swell (1★+): Tuesday 1 Sep, 6AM (local time) - 3ft (0.9m), 12s period with ESE 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 (Sep 01) at 6AM. The primary swell is predicted to be 0.9m and 12s period with a secondary swell of 0.9m and 7s. Another secondary swell of 1.1m and 7s is also forecast. 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 1.8m 13s and forecast to arrive on Monday (Sep 07) 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 1.5m 6s period and expected on Friday (Sep 04) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Tue 1st Sep) | 3ft (0.9m) 12s |
| Best Surf | 6AM (Tue 1st Sep) | 3ft (0.9m) 12s |
| Most Powerful | 9AM (Mon 7th Sep) | 6ft (1.8m) 13s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s look at what we’ve got for the area.
Right now, things are looking pretty flat. We’ve got a few days of small, junky stuff at Onjuku, but honestly, there’s nothing worth paddling out for from Monday the 31st of August through to Saturday the 6th of September. The surf is tiny, wind is cross-off, and the energy is just not there. We’re looking at weak, short-period waves with combined energy values mostly between 100 and 272 – that's just not enough to get excited about. You’ll be waiting around for nothing.
The first real standout comes on Monday the 7th of September. This is the morning to circle on the calendar. Onjuku wakes up to a clean 7 ft swell from the ESE, period around 9 seconds. The wind is light offshore from the NNE in the morning, going glassy in the afternoon. The combined energy jumps to 747, finally some proper push! The water temperature is about average for the time of year, nothing weird there. This is the best on offer. Conditions look very good, with nice, clean lines. Confident call for this one.
Tuesday the 8th keeps the party going with a 6 ft SE swell in the morning and more clean conditions. The energy is strong at 1166, so expect some decent grunt. This is a solid follow-up day for experienced surfers. The wind stays clean, though it picks up to a cross-off by the afternoon.
We then hit a messy patch. Wednesday the 9th still has some size, around 6 ft from the SE with a long 12-second period and strong energy (1136), but the wind gets stiff and cross-off, making it less appealing. From Thursday the 10th through Saturday the 12th, things get stormy and ugly. Strong cross-onshore winds, risk of thunderstorms, and the swell turns to junk. By Saturday morning, the swell is 10 ft from the SSE, but it’s blown out with fresh cross-onshore winds and lumpy conditions. That’s expert-only, if even surfable, and it looks more interesting for kite surfing than paddle surfing.
Sunday the 13th is still poor. Monday the 14th shows a bit of life with a 6 ft SE swell and light cross-onshore breeze, but it’s marginal. The combined energy is moderate, but the wind is not ideal.
Now, for the long-range promise – Tuesday the 15th of September. This is a very promising, but less certain, call. The models are showing a massive 16 ft swell from the SSE with a long 13-second period, and the combined energy is a whopping 8984. However, the note says the swell is predicted to be too big for Onjuku. The wind is cross-off from the NE, so the conditions would be clean, but this is only for the most experienced big-wave chargers. If it comes in, it’ll be a spectacle, but don’t get your hopes up until it’s closer.
Overall, the week starts slow, but the 7th and 8th of September are your true standouts. After that, it’s a mixed bag of big but messy surf, with a wildcard at the very end.
Rusty out.
Short Range ForecastSome drizzle, heaviest during Wed night. Warm (max 27°C on Wed morning, min 23°C on Mon night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 42mm), heaviest during Fri night. Warm (max 28°C on Thu morning, min 20°C on Fri night). Winds increasing (light winds from the NNE on Thu night, strong winds from the NE by Fri night). | ||||||||||||||||||||
Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | |||||||||||||||
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 14 | ESE 14 | ESE 12 | ESE 12 | ESE 11 | ESE 11 | ESE 10 | ESE 10 | ESE 11 | E 10 | E 10 | SE 7 | SE 7 | SE 7 | NE 6 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | SSE 12 | SSE 12 |
Wave Graph | |||||||||||||||||||||
56 | 73 | 175 | 237 | 214 | 210 | 146 | 111 | 123 | 73 | 71 | 128 | 54 | 37 | 116 | 247 | 440 | 322 | 237 | 371 | 509 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | glassy | glassy | on | on | on | on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off |
High Tide | 6:10PM1.43m | 6:41AM1.32m | 6:31PM1.44m | 7:30AM1.23m | 6:53PM1.43m | 8:31AM1.12m | 7:17PM1.40m | 10:14AM1.02m | 7:46PM1.36m | 8:26PM1.30m | 4:09PM1.19m | 10:16PM1.23m | |||||||||
Low Tide | 12:02PM0.43m | 00:30AM0.36m | 12:27PM0.56m | 1:09AM0.32m | 12:52PM0.70m | 1:54AM0.31m | 1:12PM0.84m | 2:52AM0.34m | 1:18PM0.97m | 4:13AM0.36m | 6:01AM0.34m | 6:12PM1.19m | |||||||||
5:09 | — | — | 5:09 | — | — | 5:11 | — | — | 5:11 | — | — | 5:11 | — | — | 5:13 | — | — | 5:13 | — | — | |
— | 6:07 | — | — | 6:06 | — | — | 6:05 | — | — | 6:04 | — | — | 6:01 | — | — | 6:00 | — | — | 5:59 | — | |
mm | — | — | — | — | — | — | — | — | 1 | 1 | — | 5 | 1 | 9 | 23 | 3 | — | — | — | — | — |
Temp °C | 25 | 25 | 24 | 26 | 26 | 24 | 27 | 27 | 27 | 28 | 28 | 25 | 25 | 23 | 21 | 22 | 23 | 23 | 24 | 24 | 24 |
Feels °C | 25 | 24 | 24 | 27 | 28 | 26 | 30 | 29 | 31 | 30 | 30 | 28 | 25 | 21 | 15 | 18 | 18 | 19 | 20 | 20 | 21 |
Swell 1 Height (m) Direction Period (s) | E 11 | ESE 14 | ESE 12 | ESE 12 | ESE 11 | ESE 11 | ESE 10 | ESE 10 | SE 6 | SE 6 | SE 6 | SE 7 | SE 7 | SE 7 | SSE 6 | SE 7 | SSW 8 | SE 12 | SE 11 | SSE 12 | E 7 |
56 | 73 | 175 | 237 | 214 | 210 | 146 | 111 | 51 | 38 | 43 | 128 | 54 | 37 | 28 | 22 | 12 | 227 | 237 | 371 | 261 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | E 11 | E 11 | SSW 8 | NE 7 | NE 7 | ENE 7 | ENE 7 | ESE 11 | E 10 | E 10 | E 10 | E 9 | SSW 9 | SSW 8 | SSW 8 | SE 16 | ENE 12 | ENE 12 | ENE 12 | SSE 12 |
23 | 56 | 36 | 14 | 46 | 21 | 28 | 18 | 123 | 73 | 71 | 48 | 43 | 26 | 33 | 21 | 10 | 14 | 14 | 14 | 509 | |
Swell 3 Height (m) Direction Period (s) | SE 14 | SE 9 | SSW 9 | ESE 15 | SSW 9 | SSW 8 | SSW 8 | ESE 6 | SSW 8 | S 8 | SE 10 | SSW 9 | S 8 | E 9 | E 9 | E 13 | E 13 | SSW 8 | S 8 | SSW 10 | SW 10 |
51 | 22 | 16 | 21 | 15 | 14 | 14 | 16 | 23 | 52 | 24 | 26 | 36 | 26 | 40 | 14 | 14 | 7 | 1 | 10 | 4 | |
Wind waves Height (m) Direction Period (s) | NE 4 | NE 5 | NE 7 | NE 7 | — | — | — | — | SE 6 | — | S 8 | — | NE 5 | NE 6 | NE 6 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | ENE 7 | — |
29 | 65 | 85 | 55 | — | — | — | — | 46 | — | 66 | — | 58 | 148 | 116 | 247 | 440 | 322 | 222 | 204 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 240 | 56 | 56 | 12 | 0 | 0 | 0 | 9 | 9 | 9 | 9 | 56 | 51 | 575 | 295 | 295 | 617 | 553 | 536 | 553 | 617 |
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.











