
Surf Forecasts:
Onjuku surf forecast from 29 Jul 2026:
- Best quality surf: Tuesday 4 Aug, 3AM (local time) - 11ft (3.5m), 17s period, SE swell with cross-offshore winds.
- Most powerful swell: Wednesday 5 Aug, 9AM (local time) - 18ft (5.5m), 17s period, SE swell with 17,752 kJ wave energy.
- Next surfable swell (1★+): Wednesday 29 Jul, 9PM (local time) - 3ft (0.9m), 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 Wednesday (Jul 29) at 9PM. The primary swell is predicted to be 0.9m and 7s period with a secondary swell of 0.4m and 9s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 5.5m 17s and forecast to arrive on Wednesday (Aug 05) 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 0.3m 2s period and expected on Thursday (Jul 30) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Wed 29th Jul) | 3ft (0.9m) 7s |
| Best Surf | 3AM (Tue 4th Aug) | 11ft (3.5m) 17s |
| Most Powerful | 9AM (Wed 5th Aug) | 18ft (5.5m) 17s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright, let me break this down for you, Onjuku style. The first week is a bit of a dud, so don’t rush down there right away.
From Wednesday the 29th through the weekend, we’re looking at weak, gutless swell. Wednesday morning has a 5ft SW swell, but it’s only 7 seconds apart and the wind is cross-onshore, so it’s messy. The energy is weak (343). Thursday morning the 30th cleans up with a light offshore from the NNE, but the swell drops to 2ft, so it’s tiny and forgettable. Friday and Saturday are the same story – small, short-period waves and nothing with any push.
Sunday morning, the 2nd of August, is where it gets interesting. The swell jumps to 4ft from the SE, and the period goes to 15 seconds – that’s real groundswell. The energy is strong at 607, and the wind is light and variable, so it could be glassy. The tide might be a factor, but it’s the best looking surf all week. Water temp is 81°, right on average for the season.
Now, the main event: Monday the 3rd of August. The swell hits 8ft from the SE with an 18-second period, and the energy is massive at 3802. The wind is a clean cross-off from the NNE. That’s big, clean, and powerful. But by Tuesday the 4th, it really blows up: 13ft to 15ft from the SE, with energy over 8000 to 10000. The wind stays clean, but this is way too big for most guys. Only the experts should even be thinking about it. The wave comment says it’s too big for this break, and I’m telling you, it’s into serious big-wave territory.
Wednesday the 5th peaks with 18ft swell and energy over 17000. Absolutely massive, but it’s beyond what Onjuku can handle for a normal session. Crowds are sometimes a thing here, but on these days, you’ll only see a handful of chargers.
Into the second week, the swell drops but stays solid. Thursday the 6th still has 8ft from the SSE, but the wind turns onshore and choppy, so the quality takes a hit. From the 7th onward, it’s smaller, weaker swells with onshore winds, and the energy drops under 1000. The cleanest window comes around the 13th of August, with a 4ft E swell and a gentle offshore from the N, giving you clean, fun waves – nothing big, but a good session.
The standout is Sunday the 2nd of August: that 4ft SE groundswell with light wind and a long period. It’s the most user-friendly, cleanest surf in the whole run. For the real heavy hitters, Monday the 3rd through Wednesday the 5th is the big-wave window, but only if you’re ready for it.
Rusty.
Short Range ForecastMostly dry. Warm (max 29°C on Wed morning, min 25°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Sun night. Warm (max 28°C on Sun morning, min 23°C on Sun night). Winds increasing (calm on Sat night, fresh winds from the NE by Mon afternoon). | ||||||||||||||||||||
Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | |||||||||||||||
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) | SW 7 | SW 7 | SSW 7 | SSW 7 | S 7 | SSW 6 | SSW 7 | S 7 | SE 11 | SE 11 | SE 16 | SE 15 | SE 15 | SE 16 | SE 16 | SE 18 | SE 17 | SE 17 | SE 17 | SE 17 | SE 17 |
Wave Graph | |||||||||||||||||||||
189 | 200 | 57 | 49 | 38 | 109 | 67 | 45 | 29 | 29 | 91 | 176 | 574 | 783 | 1750 | 3705 | 4541 | 5681 | 8273 | 10921 | 14223 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | off | cross-on | cross-on | cross-off | cross | cross-off | cross-off | cross | cross | cross | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 7:32AM1.21m | 7:51PM1.38m | ||||||||
Low Tide | 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 | 1:27PM0.54m | 2:28AM0.50m | |||||||
4:43 | — | — | 4:45 | — | — | 4:46 | — | — | 4:46 | — | — | 4:47 | — | — | 4:48 | — | — | 4:48 | — | — | |
— | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | 3 |
Temp °C | 29 | 29 | 28 | 29 | 29 | 27 | 28 | 28 | 26 | 27 | 27 | 26 | 28 | 28 | 25 | 26 | 25 | 25 | 27 | 26 | 25 |
Feels °C | 31 | 32 | 32 | 31 | 31 | 31 | 31 | 31 | 28 | 30 | 30 | 30 | 31 | 31 | 27 | 26 | 24 | 26 | 27 | 25 | 24 |
Swell 1 Height (m) Direction Period (s) | SSW 7 | SSW 7 | SSW 7 | SSW 7 | S 7 | SSW 6 | SSW 7 | S 7 | S 6 | SE 11 | ESE 11 | SE 15 | SE 15 | SE 16 | SE 16 | SE 18 | SE 17 | SE 17 | SE 17 | SE 17 | SE 17 |
102 | 111 | 57 | 49 | 38 | 44 | 67 | 45 | 26 | 29 | 40 | 176 | 574 | 783 | 1750 | 3705 | 4541 | 5681 | 8273 | 10921 | 14223 | |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 10 | SE 10 | SE 10 | SE 9 | SE 9 | SE 9 | SE 9 | NE 8 | NE 8 | SE 16 | ESE 10 | SE 5 | SE 9 | E 14 | E 14 | E 14 | E 14 | E 13 | — | — |
44 | 33 | 23 | 32 | 31 | 22 | 30 | 14 | 14 | 14 | 91 | 67 | 12 | 64 | 65 | 97 | 58 | 93 | 126 | — | — | |
Swell 3 Height (m) Direction Period (s) | ENE 6 | E 9 | E 9 | E 8 | E 8 | ENE 8 | ENE 8 | NE 8 | SE 11 | E 11 | SE 10 | SE 4 | SE 9 | E 15 | ENE 7 | — | — | — | — | — | — |
8 | 14 | 14 | 12 | 12 | 13 | 12 | 9 | 29 | 20 | 25 | 10 | 21 | 68 | 17 | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | SW 7 | SW 7 | — | ENE 2 | — | SSW 6 | — | — | ENE 3 | ESE 4 | ESE 4 | — | — | — | — | — | — | E 6 | — | — | — |
189 | 200 | — | 1 | — | 109 | — | — | 2 | 9 | 12 | — | — | — | — | — | — | 71 | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 2 | 9 | 9 | 0 | 9 | 2 | 0 | 9 | 0 | 0 | 9 | 9 | 9 | 56 | 51 | 51 | 56 | 40 | 51 | 557 | 554 |
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.










