
Surf Forecasts:
Onjuku surf forecast from 13 Sep 2026:
- Best quality surf: Saturday 19 Sep, 3AM (local time) - 10ft (3.0m), 15s period, SE swell with offshore winds.
- Most powerful swell: Saturday 19 Sep, 3AM (local time) - 10ft (3.0m), 15s period, SE swell with 4,234 kJ wave energy.
- Next surfable swell (1★+): Tuesday 15 Sep, 9PM (local time) - 2.5ft (0.7m), 13s period with E 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 15) at 9PM. The primary swell is predicted to be 0.7m and 13s period with a secondary swell of 1.1m and 7s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 3.0m 15s and forecast to arrive on Saturday (Sep 19) at 3AM. 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 Thursday (Sep 17) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Tue 15th Sep) | 2.5ft (0.7m) 13s |
| Best Surf | 3AM (Sat 19th Sep) | 10ft (3.0m) 15s |
| Most Powerful | 3AM (Sat 19th Sep) | 10ft (3.0m) 15s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s talk about what’s on offer for Onjuku over the next couple of weeks. It’s a bit of a slow start, but there are a few moments that could be worth paddling out for, and one stretch that looks like a real treat if you’ve got the experience.
The water temp is sitting at a comfortable 79° – pretty much spot on for this time of year, nothing unusual there.
Alright, the first real chance to get wet comes on Sunday the 13th. The afternoon’s looking clean with glassy conditions and a small 2ft swell rolling in from the ESE, with a period of 13 seconds. That’s a nice long-period groundswell, which means better-shaped waves but longer lulls between sets. The combined energy is moderate at 239, so don’t expect much push. It’s a gentle start, but the wind is dead calm, so you’ll be surfing clean little peelers.
Then we hit a bit of a dry spell. From Monday the 14th through most of Tuesday the 15th, the wind turns onshore and the surf quality drops off. It’s not worth your time. Wednesday the 16th brings a glimmer of hope – morning and afternoon both see clean conditions with a cross-offshore breeze and a small 2ft swell from the east. The energy is moderate (296 in the morning, 203 in the afternoon) and the period is a solid 12-13 seconds. It’s not pumping, but it’s surfable and tidy.
Thursday the 17th gets messy again with strong cross-offshore winds, and by the afternoon the swell bumps up to 6ft but with a short, weak period of 7 seconds – that’s junk, even if it looks big. Friday the 18th sees the wind go offshore, which is a big positive, but the morning swell is still that short-period 6ft from the ENE (energy 703 – moderate to strong) – it’s a bit of a mixed bag. The afternoon though, things get interesting. The swell switches to a 6ft SE groundswell with a very long 17-second period, and the combined energy jumps to a strong 2460. That’s proper energy, and with fresh offshore winds, the lines should be clean and powerful. This is a standout moment for experienced surfers – the point break setup at Onjuku will really appreciate that long-period SE swell.
Saturday the 19th sees the swell push up to 10ft from the SE, with periods around 12-13 seconds and very strong energy (3879 in the morning). But the wind is cross-offshore in the morning and cross-shore in the afternoon, so it’ll be a bit lumpy. Still, that’s a lot of water moving.
The real highlight of the whole run is Sunday the 20th. The swell holds at 10ft from the SE, with a 12-second period and combined energy of 2035-2331 (very strong). The wind is light to moderate offshore from the north. This is excellent surf for experienced surfers – big, clean, powerful waves. If you’re an expert, this is your window. The break can get crowded sometimes, so keep that in mind.
Monday the 21st goes to hell in a handbasket – strong onshore winds, a big messy 8-10ft swell, and completely blown out. Skip it. Tuesday the 22nd is plain dangerous – the swell hits 18-23ft with extreme energy (over 20,000). That’s way too big for this break, even for experts.
After that, the surf settles down through the rest of the week and into the following weekend. Wednesday the 23rd through Saturday the 26th mostly offers small, clean but weak waves. The best of that stretch is Friday the 25th morning, with a 5ft east-northeast swell, 7-second period, and glassy conditions – combined energy 359 (moderate). It’s small and short-period, but clean.
Then Sunday the 27th morning brings a surprise – glassy conditions again with a 8ft swell from the ENE, 8-second period, and combined energy of 1168 (strong). That’s a solid wave for experienced surfers, and with no wind it’ll be glassy. The period is short though, so it might be a bit crumbly.
Monday the 28th sees the wind turn onshore again, making things choppy with a 7-7ft SE swell. Not one for the quiver.
So, the standout window is definitely Friday the 18th afternoon through Sunday the 20th, with Sunday the 20th being the pick – big, offshore, clean, and powerful. If you’re experienced and can handle 10ft waves, that’s the one.
Rusty.
Short Range ForecastHeavy rain (total 24mm), heaviest during Wed morning. Warm (max 27°C on Mon morning, min 22°C on Wed morning). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 35mm), heaviest during Sat morning. Warm (max 24°C on Fri afternoon, min 20°C on Thu night). Winds increasing (light winds from the NE on Wed night, strong winds from the NNE by Thu night). | |||||||||||||||||||
Sun 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | Saturday 19 | ||||||||||||||
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) | ESE 13 | E 12 | SE 10 | SE 9 | SE 9 | E 14 | E 14 | E 13 | E 13 | E 12 | E 12 | E 12 | ENE 7 | NE 7 | ENE 7 | SE 17 | SE 15 | SE 13 | SE 12 | SE 12 |
Wave Graph | ||||||||||||||||||||
178 | 108 | 77 | 147 | 231 | 195 | 196 | 167 | 215 | 148 | 138 | 97 | 332 | 362 | 332 | 2140 | 4192 | 3514 | 2834 | 2296 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | cross-on | cross-on | cross-on | cross-on | cross-on | glassy | cross-off | cross-off | cross-off | cross-off | cross-off | off | off | off | cross-off | cross-off | cross | cross |
High Tide | 5:26PM1.43m | 6:04AM1.38m | 5:44PM1.44m | 6:45AM1.29m | 6:03PM1.43m | 7:26AM1.19m | 6:22PM1.41m | 8:14AM1.09m | 6:42PM1.37m | 9:27AM0.99m | 7:03PM1.31m | 7:24PM1.24m | ||||||||
Low Tide | 11:46PM0.30m | 11:50AM0.57m | 00:19AM0.26m | 12:11PM0.69m | 00:53AM0.27m | 12:28PM0.79m | 1:31AM0.32m | 12:40PM0.87m | 2:15AM0.40m | 12:34PM0.94m | 3:18AM0.48m | |||||||||
— | — | 5:18 | — | — | 5:20 | — | — | 5:20 | — | — | 5:22 | — | — | 5:22 | — | — | 5:22 | — | — | |
5:49 | — | — | 5:47 | — | — | 5:46 | — | — | 5:45 | — | — | 5:44 | — | — | 5:42 | — | — | 5:40 | — | |
mm | — | — | — | — | — | 1 | 1 | 10 | 12 | 6 | 7 | 2 | 1 | — | — | 2 | 9 | 8 | 12 | 41 |
Temp °C | 24 | 25 | 27 | 27 | 25 | 24 | 25 | 24 | 23 | 23 | 23 | 22 | 22 | 20 | 23 | 24 | 24 | 24 | 23 | 24 |
Feels °C | 28 | 29 | 28 | 28 | 26 | 25 | 28 | 28 | 25 | 25 | 25 | 20 | 19 | 16 | 21 | 23 | 24 | 25 | 24 | 27 |
Swell 1 Height (m) Direction Period (s) | ESE 13 | ESE 9 | SE 10 | SE 9 | SE 9 | SE 8 | SE 7 | SE 7 | SE 7 | SE 7 | E 12 | E 12 | E 11 | E 12 | SE 18 | SE 17 | SE 15 | SE 13 | SE 12 | SE 12 |
178 | 52 | 77 | 147 | 231 | 160 | 140 | 134 | 67 | 49 | 138 | 97 | 61 | 65 | 206 | 2140 | 4192 | 3514 | 2834 | 2296 | |
Swell 2 Height (m) Direction Period (s) | ENE 6 | E 12 | ESE 9 | E 12 | E 14 | E 14 | E 14 | E 13 | E 13 | E 12 | SE 8 | SE 7 | E 13 | SSE 9 | E 12 | SE 7 | E 11 | — | SSE 16 | ESE 10 |
25 | 108 | 45 | 112 | 189 | 195 | 196 | 167 | 215 | 148 | 64 | 27 | 14 | 7 | 42 | 54 | 37 | — | 376 | 1000 | |
Swell 3 Height (m) Direction Period (s) | SE 9 | SSE 7 | E 12 | ENE 7 | ENE 7 | S 7 | S 7 | NNE 4 | SE 9 | SSW 5 | E 16 | E 15 | SE 9 | — | SE 22 | E 11 | — | — | — | — |
36 | 19 | 76 | 9 | 10 | 1 | 1 | 5 | 14 | 6 | 5 | 4 | 3 | — | 123 | 58 | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | SSW 3 | SSW 4 | S 7 | — | — | NE 3 | NE 5 | NE 5 | NE 5 | NE 6 | ENE 7 | NE 7 | ENE 7 | NE 7 | NE 11 | ENE 10 | ENE 9 | — |
— | — | 2 | 13 | 1 | — | — | 6 | 35 | 62 | 25 | 124 | 332 | 362 | 332 | 208 | 408 | 365 | 266 | — | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 0 | 9 | 143 | 583 | 110 | 18 | 2 | 0 | 0 | 0 | 0 | 206 | 553 | 536 | 295 | 206 | 536 | 575 | 51 | 51 |
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.










