Surf Forecasts:
Onjuku surf forecast from 30 Jul 2026:
- Best quality surf: Tuesday 4 Aug, 12PM (local time) - 11ft (3.5m), 16s period, SE swell with cross-offshore winds.
- Most powerful swell: Thursday 6 Aug, 6AM (local time) - 15ft (4.5m), 17s period, SSE swell with 12,115 kJ wave energy.
- Next surfable swell (1★+): Friday 31 Jul, 12AM (local time) - 2.5ft (0.7m), 6s 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 Friday (Jul 31) at 12AM. The primary swell is predicted to be 0.7m and 6s 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 17s and forecast to arrive on Thursday (Aug 06) at 6AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Monday (Aug 03) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Fri 31st Jul) | 2.5ft (0.7m) 6s |
| Best Surf | 12PM (Tue 4th Aug) | 11ft (3.5m) 16s |
| Most Powerful | 6AM (Thu 6th Aug) | 15ft (4.5m) 17s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Right, let’s have a look at what’s coming up for the next couple of weeks here. I’m Rusty, and I’ll take you through it.
We’ve got a bit of a slow start, but don’t write it off. The first few days are pretty flat or just offering small, weak junk. Thursday morning the 30th of July has a tiny 1ft SSE swell, but with a slight onshore wind and weak energy (67), it's a flat spell. Friday the 31st and Saturday the 1st of August see a slight lift to 3ft and 1ft, but it’s ordinary at best. You could get wet, but there’s nothing to get excited about.
Now, Sunday the 2nd of August is where the story starts to get interesting. The morning at Onjuku shows a jump to 4ft from the SE, with a very long 16-second period and solid energy (650). The wind is a light cross-offshore from the NE, so it’ll be clean. The water’s about average for the time of year at 80°. This is a promising window, but the swell direction is SSE and the break really likes it from that direction. Still, it’s the first real standout in the run.
The real heavyweight event is brewing for the start of the following week. From Monday the 3rd of August through to Wednesday the 5th, the swell just goes nuts. We’re talking 7ft on Monday morning, ramping up to a massive 15ft by Wednesday afternoon. This is all from the SE, with a very long 16-17 second period. The energy numbers are huge – into the thousands (2,760 up to 10,357). This is for experts only. The wind stays cross-offshore and clean, but the guidance is clear: the swell is predicted to be too big for this break. It’s going to be a serious, powerful beast. If you’re not a pro, stay on the beach. Thursday and Friday the 6th and 7th still hold a big 13ft to 8ft, but with cross-shore winds and a risk of thunderstorms, it’s looking less appealing.
After that big pulse, the second week settles down. Saturday the 8th drops to 5ft, and Sunday the 9th of August offers a nice clean 5ft from the ESE in the morning with a light cross-offshore breeze (15 km/h) and good energy (994). That’s your best bet for a manageable, fun-sized wave later in the period. We then see windows of 5ft to 4ft with clean winds through to around Wednesday the 12th, but nothing else really jumps out as a true standout. The run fizzles out after that with stronger winds and poorer conditions.
So, if you’re after a decent paddle, your standout call is Sunday the 2nd of August for the first clean, building swell. For the brave and the expert, the big pulse from Monday the 3rd to Wednesday the 5th will be a spectacle, but it’s serious. For a classic, clean session later on, target Sunday the 9th of August.
Rusty.
Short Range ForecastMostly dry. Warm (max 29°C on Thu morning, min 26°C on Fri night). Wind will be generally light. | Days 4-6 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 | Wednesday 5 | |||||||||||||||
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 9 | SE 9 | SSW 6 | SSW 7 | S 6 | SE 11 | SE 11 | SE 16 | SE 18 | SE 16 | SE 15 | SE 16 | SE 17 | SE 18 | SE 16 | SE 16 | SE 16 | SE 16 | SE 16 | SSE 17 | SSE 17 |
Wave Graph  | |||||||||||||||||||||
 kJ | 31 | 31 | 44 | 47 | 31 | 29 | 29 | 93 | 194 | 739 | 733 | 1728 | 2947 | 4336 | 4435 | 5169 | 6473 | 6365 | 8195 | 10925 | 11931 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | cross-on | glassy | cross-off | cross | cross | glassy | cross | glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 8:31AM1.11m | 8:17PM1.37m | ||||||||
Low Tide | 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 | 1:55PM0.69m | ||||||||
 |  |  | | | | | |  | | | | | | | | | | | |  | |
 | 4:45 | — | — | 4:46 | — | — | 4:46 | — | — | 4:47 | — | — | 4:48 | — | — | 4:48 | — | — | 4:48 | — | — |
 | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:38 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 |
Temp °C | 29 | 29 | 28 | 29 | 29 | 27 | 29 | 29 | 27 | 29 | 28 | 24 | 25 | 25 | 23 | 26 | 26 | 24 | 27 | 27 | 26 |
Feels °C | 32 | 32 | 33 | 32 | 32 | 31 | 32 | 33 | 32 | 32 | 31 | 25 | 24 | 24 | 23 | 26 | 27 | 26 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | S 7 | SE 9 | SSW 6 | SSW 7 | S 6 | SSW 6 | S 6 | S 6 | ESE 10 | SE 16 | SE 15 | SE 16 | SE 17 | SE 18 | SE 16 | SE 16 | SE 16 | SE 16 | SE 16 | SSE 17 | SSE 17 |
| kJ | 24 | 31 | 44 | 47 | 31 | 16 | 15 | 18 | 67 | 739 | 733 | 1728 | 2947 | 4336 | 4435 | 5169 | 6473 | 6365 | 8195 | 10925 | 11931 |
Swell 2 Height (m) Direction Period (s) | SE 9 | E 8 | SE 9 | SE 9 | SE 9 | SE 11 | NE 8 | ESE 10 | SE 18 | NE 7 | ESE 9 | E 14 | E 14 | E 14 | E 14 | E 13 | E 13 | E 13 | E 11 | — | ENE 16 |
| kJ | 31 | 12 | 22 | 30 | 13 | 29 | 14 | 36 | 194 | 12 | 70 | 65 | 34 | 61 | 58 | 90 | 84 | 86 | 410 | — | 26 |
Swell 3 Height (m) Direction Period (s) | E 8 | SE 12 | E 8 | ENE 8 | ENE 8 | NE 8 | SE 11 | SE 16 | SE 14 | E 16 | E 15 | — | — | — | — | — | — | — | E 18 | — | — |
| kJ | 12 | 6 | 5 | 13 | 6 | 15 | 29 | 93 | 103 | 43 | 67 | — | — | — | — | — | — | — | 25 | — | — |
Wind waves Height (m) Direction Period (s) | — | S 6 | — | — | ENE 3 | SE 3 | SE 3 | SE 3 | — | — | — | NE 4 | NE 5 | NE 5 | NE 6 | NE 7 | NE 7 | NE 7 | — | E 11 | E 10 |
| kJ | — | 24 | — | — | 3 | 3 | 2 | 2 | — | — | — | 12 | 30 | 40 | 80 | 86 | 69 | 65 | — | 526 | 476 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 18 | 0 | 0 | 9 | 6 | 0 | 9 | 0 | 0 | 56 | 51 | 51 | 56 | 51 | 51 | 51 | 40 | 51 | 68 | 51 |
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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