
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, 12PM (local time) - 15ft (4.5m), 16s period, SSE swell with 10,532 kJ wave energy.
- Next surfable swell (1★+): Thursday 30 Jul, 6AM (local time) - 2ft (0.6m), 7s period with S 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 6AM. The primary swell is predicted to be 0.6m 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 4.5m 16s and forecast to arrive on Wednesday (Aug 05) at 12PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Friday (Jul 31) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Thu 30th Jul) | 2ft (0.6m) 7s |
| Best Surf | 3AM (Tue 4th Aug) | 11ft (3.5m) 17s |
| Most Powerful | 12PM (Wed 5th Aug) | 15ft (4.5m) 16s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s look ahead at Onjuku because for the next 16 days there’s a real split on the cards—small, ordinary stuff early, then a solid pulse that turns into some giant, expert-only action, and finally a glassy autumn-like finish.
Right now through Thursday morning, it’s flat and poor. Thursday morning on July 30th has a tiny 2ft, 7-second windswell from the south on a southerly breeze that’s right onshore—rubbish. That afternoon is even smaller at 1.3ft, 9 seconds from the southeast with a side-onshore wind. Don’t bother.
Friday July 31st morning kicks off the first real surfable window. Swell is still only 2.3ft from the SSW, 7-second period, but the wind is a light cross-offshore at 6 mph, giving clean enough conditions for an inconsistent spot like Onjuku. Combined energy is weak at 91. It’s nothing to get excited about, but you can get wet. Afternoon sees the wind go cross-shore from the ESE at 9 mph and quality drops.
Saturday August 1st stays weak. Morning has a 1.3ft, 11-second swell from the southeast, combined energy only 72, with an onshore cross breeze. Afternoon the period jumps to 16 seconds but still only 1.3ft, combined energy 169—moderate energy but no push.
Sunday August 2nd morning, things start to wake up. The swell comes from the SE at 3.9ft with a long 16-second period. Combined energy hits 767 (moderate). Wind is light cross-off from the ENE at 6 mph—clean. That’s a solid little pulse. Afternoon gets a bit fatter at 4.3ft, 16 seconds, combined energy 913, but the wind turns cross-shore from the ESE at 9 mph and creates some cross-chop.
Monday August 3rd morning sees the swell jump to 7.9ft from the SE, 18-second period, combined energy a strong 3544. Wind is cross-off from the NE at 12 mph—clean. Conditions are there but the size is pushing it for average intermediate surfers. Afternoon hits 9.8ft, 18 seconds, energy 4968—still clean, but now only for experienced paddlers.
Tuesday August 4th morning is where it gets brutal. Swell 11.5ft from the SE, 17 seconds, combined energy 7444 (very strong). Wind is cross-off NE at 12 mph—clean. But the wave comment says it all: this is too big for Onjuku. Expert only, and only if you know the sandbar. Afternoon is 13.1ft, 17 seconds, energy 9439—same deal, too big for general surfing.
Wednesday August 5th peaks with 14.8ft, 16 seconds from the SSE, energy 10535. Clean from a cross-off NE breeze at 9 mph. But this is kite-surf territory for anyone without serious big-wave experience. Same again Thursday August 6th, still 13.1ft, 16 seconds, energy in the 8000s, with side-off wind that leaves some chop.
Friday August 7th morning, the swell drops to 8.2ft from the S, 15-second period, still strong energy at 3186. Light cross-off wind from the ENE at 6 mph, clean—this is the standout for experienced surfers. It’s still solid but not out of control, and the wind is kind. Crowds are sometimes an issue at Onjuku, so expect company.
Saturday August 8th morning drops to 4.6ft from the ESE, 14 seconds, energy 1968 (moderate), with a clean cross-off breeze. Good for intermediates. Afternoon bumps to 5.6ft, 17 seconds, still clean.
Sunday August 9th is windy: NE 19 mph cross-off, swell 5.9ft from the ESE, 15–14 seconds, energy around 1700. That’s fresh wind, but the swell is there. Same vibe Monday August 10th and Tuesday August 11th: NE wind 19–22 mph, swell 6.2–7.5ft from the ESE to E, periods 14–18 seconds, energy up to 3139. Clean but windblown by the fresh breeze.
Wednesday August 12th morning is the quiet gem. Swell 5.2ft from the east, 12-second period, combined energy 805 (moderate). Wind is glassy—literally calm from the north at 3 mph. This is as clean as it gets. Afternoon goes south with sea breeze ruin.
Thursday August 13th morning is 3.6ft from the SE, 10 seconds, energy 509, with a moderate cross-off breeze—clean, small. That afternoon is 3.3ft, same direction, similar wind, but poor quality.
Friday August 14th morning finishes the outlook with 2.6ft from the SSE, 10 seconds, energy 338, and a risk of thunderstorms with a moderate cross-off breeze. Very marginal.
Best on offer: Sunday morning August 2nd for the first proper clean swell pulse, and Friday morning August 7th for the best combo of size, period, and light offshore wind for stronger surfers. Wednesday August 12th morning is the glassy gem for a relaxed session.
Short Range ForecastMostly dry. Warm (max 29°C on Thu morning, min 26°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 29°C on Sun morning, min 23°C on Mon night). Wind will be generally light. | ||||||||||||||||||
Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | ||||||||||||||
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 7 | S 7 | SE 9 | SW 6 | SSW 7 | S 7 | SE 9 | SE 11 | SE 16 | SE 15 | SE 16 | SE 16 | SE 16 | SE 18 | SE 18 | SE 17 | SE 17 | SE 17 | SE 16 |
Wave Graph | |||||||||||||||||||
52 | 34 | 31 | 71 | 48 | 42 | 31 | 29 | 93 | 174 | 711 | 803 | 1591 | 3483 | 4871 | 5357 | 7316 | 9353 | 8929 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | on | glassy | cross-off | cross | cross | cross | cross | glassy | cross-off | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 10:38PM0.90m | 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 | ||||||
— | 4:45 | — | — | 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 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 28 | 29 | 29 | 27 | 29 | 29 | 26 | 28 | 28 | 26 | 29 | 29 | 27 | 26 | 25 | 24 | 26 | 26 | 25 |
Feels °C | 32 | 32 | 32 | 31 | 32 | 32 | 30 | 31 | 31 | 31 | 32 | 32 | 31 | 26 | 25 | 25 | 26 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | SSW 7 | S 7 | SE 9 | SSW 6 | SSW 7 | S 7 | SSW 6 | SE 11 | ESE 10 | SE 15 | SE 16 | SE 16 | SE 16 | SE 18 | SE 18 | SE 17 | SE 17 | SE 17 | SE 16 |
52 | 34 | 31 | 29 | 48 | 42 | 14 | 29 | 35 | 174 | 711 | 803 | 1591 | 3483 | 4871 | 5357 | 7316 | 9353 | 8929 | |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 9 | E 8 | SE 9 | SE 9 | SE 9 | SE 9 | ESE 11 | SE 16 | ESE 10 | SE 4 | E 15 | E 14 | E 14 | E 14 | E 14 | E 13 | E 13 | — |
23 | 31 | 12 | 22 | 30 | 13 | 31 | 22 | 93 | 67 | 13 | 38 | 65 | 61 | 97 | 94 | 128 | 86 | — | |
Swell 3 Height (m) Direction Period (s) | E 9 | E 8 | SE 12 | E 8 | ENE 8 | ENE 8 | NE 8 | NE 7 | SE 11 | SE 4 | E 16 | NE 7 | ENE 7 | — | — | — | — | — | — |
14 | 12 | 6 | 5 | 13 | 6 | 15 | 14 | 30 | 11 | 43 | 8 | 4 | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | S 6 | SW 6 | — | ENE 3 | ENE 3 | SE 4 | SE 4 | — | — | SE 9 | E 7 | — | — | — | — | — | — |
— | — | 17 | 71 | — | 3 | 2 | 7 | 11 | — | — | 64 | 14 | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 9 | 18 | 0 | 0 | 135 | 579 | 579 | 9 | 0 | 0 | 9 | 51 | 51 | 51 | 51 | 51 | 68 | 40 |
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.










