
Surf Forecasts:
Onjuku surf forecast from 3 Sep 2026:
- Best quality surf: Thursday 10 Sep, 12AM (local time) - 8ft (2.4m), 10s period, SSE swell with offshore winds.
- Most powerful swell: Tuesday 8 Sep, 12PM (local time) - 13ft (4.0m), 11s period, S swell with 3,236 kJ wave energy.
- Next surfable swell (1★+): Friday 4 Sep, 3AM (local time) - 1.5ft (0.5m), 9s 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 Friday (Sep 04) at 3AM. The primary swell is predicted to be 0.5m and 9s period with a secondary swell of 0.6m and 6s. Another secondary swell of 0.5m and 4s is also forecast. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 4.0m 11s and forecast to arrive on Tuesday (Sep 08) at 12PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 6s period and expected on Saturday (Sep 05) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Fri 4th Sep) | 1.5ft (0.5m) 9s |
| Best Surf | 12AM (Thu 10th Sep) | 8ft (2.4m) 10s |
| Most Powerful | 12PM (Tue 8th Sep) | 13ft (4.0m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Right then, let's have a look at what Onjuku's got lined up for us.
Honestly, the next week and a half is looking pretty grim. There's a lot of swell on the cards, especially from the 6th of September onwards, but the wind and conditions are going to be all over the shop. We're looking at a long stretch of poor surf, with only a couple of fleeting moments where it might be worth getting wet.
Things kick off on Thursday the 3rd, but it's nothing to write home about. We've got a small 2-foot swell from the east, but with a 12 mph cross-onshore breeze it's going to be choppy and messy. The water temp is sitting at 79°, which is about average for this time of year, so at least you won't need a steamer.
Friday the 4th offers a slight glimmer. The swell stays small at 2-foot, but shifting to a south direction with a light offshore breeze in the morning. It'll be clean, but the wave energy is moderate at best (153). It's surfable, but very ordinary. The afternoon is similar with a light cross-off breeze. Saturday the 5th is a write-off, with the wind picking up and the swell turning messy, despite a brief spike in energy to 235 on the Saturday afternoon from a short period 5-foot easterly.
From Sunday the 6th through to the 10th of September, the swell gets serious, but so does the wind. We're looking at waves well over 8-foot, which is expert territory, but with strong onshore and cross-onshore winds, it'll be a bumpy, blown-out mess. The combined energy readings are strong to very strong (hitting 2433 on the 8th), but it's all for nothing with the conditions. The 8th of September has a massive 10-foot SSE groundswell with a period of 11 seconds, but a 19 mph cross-onshore will ruin it.
The 11th and 12th of September drop off in size but the wind stays strong. The 12th has a long period 2-foot easterly swell (14 seconds) and clean conditions, but it's tiny. There's a bit more life on the 14th of September. Monday morning brings a 4-foot ESE swell with a gentle 9 mph cross-off breeze, and the wave comment says "expect good surf conditions." The energy is moderate (342), and it's the first proper window we've seen. It's not a standout, but it's the best of a bad bunch.
For a true standout, you'd have to look at the 18th of September. It's a long way off, so take it with a pinch of salt, but Friday the 18th has a glassy morning with a 3 mph north wind and a small 2-foot NE swell. The wave energy is weak (157), but glassy conditions with clean surf are a rare treat. It's not going to be big, but it'll be the cleanest wave we've seen in a fortnight.
So, to sum it up: don't hold your breath for the next week. The 14th of September is your best early shout for some clean, small waves. If you're patient, the 18th of September has the best chance of clean, glassy conditions. Keep an eye on the forecasts, because a run this poor tends not to last.
Rusty.
Short Range ForecastHeavy rain (total 81mm), heaviest during Fri night. Warm (max 29°C on Thu afternoon, min 20°C on Fri night). Winds increasing (calm on Thu night, strong winds from the NE by Sun morning). | Days 5-7 Weather SummaryHeavy rain (total 192mm), heaviest during Sun night. Warm (max 28°C on Wed morning, min 23°C on Sun afternoon). Winds decreasing (strong winds from the SSE on Mon afternoon, light winds from the SW by Tue afternoon). | |||||||||||||||||||
Thu 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | ||||||||||||||
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) | E 10 | E 10 | S 10 | S 10 | S 9 | S 10 | E 6 | ENE 6 | ENE 7 | ENE 8 | E 9 | E 9 | E 9 | SSE 9 | SSE 11 | SSE 10 | SSE 10 | SSE 9 | SSE 9 | SSE 10 |
Wave Graph | ||||||||||||||||||||
71 | 68 | 73 | 70 | 61 | 47 | 162 | 303 | 571 | 1156 | 1493 | 702 | 463 | 1043 | 2353 | 2165 | 1019 | 658 | 845 | 1022 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | cross-on | cross-on | cross-on | cross-on | on | on | on | off |
High Tide | 7:17PM1.40m | 10:14AM1.02m | 7:46PM1.36m | 8:26PM1.30m | 4:09PM1.19m | 10:16PM1.23m | 3:44PM1.25m | 00:42AM1.25m | 3:57PM1.30m | 2:06AM1.33m | 4:14PM1.34m | |||||||||
Low Tide | 2:52AM0.34m | 1:18PM0.97m | 4:13AM0.36m | 6:01AM0.34m | 6:12PM1.19m | 7:30AM0.27m | 8:17PM1.09m | 8:30AM0.20m | 8:59PM0.95m | 9:17AM0.17m | 9:34PM0.80m | |||||||||
— | — | 5:11 | — | — | 5:13 | — | — | 5:13 | — | — | 5:13 | — | — | 5:15 | — | — | 5:16 | — | — | |
6:04 | — | — | 6:01 | — | — | 6:00 | — | — | 5:59 | — | — | 5:58 | — | — | 5:57 | — | — | 5:54 | — | |
mm | 3 | 1 | 1 | — | 60 | 10 | 1 | 2 | 3 | 3 | 102 | 18 | 30 | 24 | — | 1 | 10 | 4 | 4 | 17 |
Temp °C | 29 | 24 | 25 | 25 | 23 | 21 | 22 | 23 | 23 | 24 | 26 | 27 | 27 | 27 | 27 | 27 | 27 | 28 | 28 | 28 |
Feels °C | 31 | 24 | 27 | 27 | 23 | 19 | 19 | 19 | 19 | 20 | 26 | 27 | 24 | 26 | 27 | 31 | 30 | 28 | 28 | 28 |
Swell 1 Height (m) Direction Period (s) | E 10 | ENE 4 | SE 6 | S 10 | S 9 | S 10 | SSW 9 | SSW 8 | SSW 9 | S 8 | SSW 10 | E 9 | E 9 | SSE 9 | SSE 11 | SSE 10 | SSE 10 | SSE 9 | E 16 | SSE 10 |
71 | 23 | 39 | 70 | 61 | 47 | 28 | 14 | 8 | 12 | 10 | 702 | 463 | 1043 | 2353 | 2165 | 1019 | 658 | 20 | 1022 | |
Swell 2 Height (m) Direction Period (s) | SSW 8 | E 10 | S 10 | E 9 | SE 7 | E 9 | ENE 13 | SE 12 | S 8 | — | — | SSE 8 | SSE 8 | ENE 9 | ENE 9 | E 9 | NE 7 | NNE 6 | NNE 7 | E 15 |
24 | 68 | 73 | 58 | 27 | 25 | 33 | 6 | 5 | — | — | 120 | 264 | 222 | 80 | 39 | 7 | 4 | 5 | 18 | |
Swell 3 Height (m) Direction Period (s) | E 6 | S 8 | E 9 | SE 6 | E 9 | SE 9 | SE 9 | SW 9 | SE 12 | — | — | SE 11 | E 18 | E 18 | — | NNE 7 | E 18 | E 16 | NNE 7 | NNE 7 |
13 | 35 | 41 | 25 | 41 | 12 | 12 | 3 | 6 | — | — | 30 | 6 | 6 | — | 18 | 6 | 21 | 5 | 5 | |
Wind waves Height (m) Direction Period (s) | S 4 | — | NE 4 | — | NE 3 | E 6 | E 6 | ENE 6 | ENE 7 | ENE 8 | E 9 | WNW 3 | NNE 3 | — | — | — | — | — | SSE 9 | NNE 4 |
15 | — | 5 | — | 2 | 127 | 162 | 303 | 571 | 1156 | 1493 | 8 | 4 | — | — | — | — | — | 845 | 3 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 142 | 9 | 0 | 0 | 51 | 51 | 206 | 617 | 536 | 536 | 536 | 51 | 206 | 101 | 88 | 18 | 9 | 200 | 577 | 0 |
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.










