
Surf Forecasts:
Onjuku surf forecast from 7 Sep 2026:
- Best quality surf: Wednesday 9 Sep, 9PM (local time) - 6.5ft (2.0m), 9s period, S swell with offshore winds.
- Most powerful swell: Monday 7 Sep, 12PM (local time) - 10ft (3.0m), 9s period, S swell with 1,689 kJ wave energy.
- Next surfable swell (1★+): Wednesday 9 Sep, 9PM (local time) - 6.5ft (2.0m), 9s 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 Wednesday (Sep 09) at 9PM. The primary swell is predicted to be 2.0m and 9s period with a secondary swell of 0.2m and 16s. Another secondary swell of 1.7m and 7s is also forecast. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Onjuku in the next 16 days are 3.0m 9s and forecast to arrive on Monday (Sep 07) at 12PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 6s period and expected on Thursday (Sep 10) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Wed 9th Sep) | 6.5ft (2.0m) 9s |
| Best Surf | 9PM (Wed 9th Sep) | 6.5ft (2.0m) 9s |
| Most Powerful | 12PM (Mon 7th Sep) | 10ft (3.0m) 9s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's get stuck into what's heading our way for Onjuku.
The next couple of weeks are a bit of a mixed bag, but we’ve got some real magic lurking in the second week to get excited about. The early part of the period is a write-off, but hang in there.
Monday the 7th is a total no-go. Onjuku is getting hammered by a strong southerly wind and a solid 10ft S swell, but the energy is all over the shop (1647) and the wind is blowing straight onshore. The water is a warm 82°, which is a touch warmer than normal for this time of year, but that won't help you with the terrible conditions. That westerly pattern sticks around through Tuesday the 8th, Wednesday the 9th, and Thursday the 10th, with onshore and cross-onshore winds keeping the surf messy and blown-out. A few small windows of clean conditions appear on Thursday, but the swell is weak and short-period.
Friday the 11th and Saturday the 12th finally see a little relief. A light offshore wind from the north on Friday will clean up the tiny 2ft E swell, but it's a super long 14-second period with low energy (183). It’s surfable, but you’ll be working for it. Saturday is similar, just a bit more onshore. The whole first week is a grind, with just small, weak, and inconsistent waves about.
Now, you’ll want to mark your calendar for the weekend starting Saturday the 19th. After a long gap of mediocre conditions, things start to look up. On Saturday the 19th, a clean 5ft swell from the ENE (212) with a light offshore wind from the north in the morning. The afternoon is looking glassy, with a slight offshore breeze. That’s your best windows of the first real run.
But the real standout is Monday the 21st of September. This is a big, long-period groundswell from the SE with a period of 18 seconds and a massive amount of energy (3268 in the morning, 5223 in the afternoon). Sizes climb from 6ft up to 8ft. The wind is a clean cross-offshore from the NE, keeping it tidy. This is the kind of swell that has real power, and with that period, it’ll be proper at Onjuku’s exposed banks. The only downside? It’s a week and a half away, so treat it as a promising call, but don’t book the week off just yet.
Now, a word of caution for Tuesday the 22nd. The models are showing a massive 13ft ESE swell with a 17-second period and energy readings over 9000. That is way too big for Onjuku. The wind is favorable, but unless you’re a tow-in expert, this is a "stay on the beach and watch" kind of day. It’s strictly for the pros.
So, to wrap it up: the first week is a washout. Saturday the 19th is a nice little warm-up. Monday the 21st is the one to chase, with a solid, powerful groundswell and clean conditions. Get keen.
Rusty.
Short Range ForecastHeavy rain (total 49mm), heaviest during Wed night. Warm (max 29°C on Wed morning, min 21°C on Wed night). Winds decreasing (strong winds from the S on Mon morning, light winds from the SW by Wed afternoon). | Days 4-6 Weather SummaryLight rain (total 8mm), mostly falling on Thu morning. Warm (max 25°C on Sat morning, min 21°C on Thu morning). Wind will be generally light. | ||||||||||||||||||||
Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | |||||||||||||||
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) | S 9 | S 9 | S 9 | SSE 9 | S 9 | S 8 | S 8 | S 9 | S 9 | NE 7 | ENE 7 | ESE 14 | E 14 | E 14 | E 14 | E 14 | E 13 | E 13 | E 13 | E 13 | SE 10 |
Wave Graph | |||||||||||||||||||||
1299 | 1553 | 1273 | 627 | 649 | 513 | 703 | 856 | 398 | 167 | 165 | 67 | 106 | 100 | 136 | 134 | 128 | 128 | 86 | 123 | 204 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross-on | on | cross-on | cross-on | cross-on | off | cross-off | cross-off | cross-off | off | off | cross-off | cross-off | cross | cross-off | cross-off | cross | on |
High Tide | 3:44PM1.25m | 00:42AM1.25m | 3:57PM1.30m | 2:06AM1.33m | 4:14PM1.34m | 3:06AM1.40m | 4:32PM1.36m | 3:56AM1.45m | 4:50PM1.39m | 4:41AM1.47m | 5:08PM1.41m | 5:24AM1.44m | 5:26PM1.43m | ||||||||
Low Tide | 8:17PM1.09m | 8:30AM0.20m | 8:59PM0.95m | 9:17AM0.17m | 9:34PM0.80m | 9:55AM0.18m | 10:07PM0.64m | 10:29AM0.24m | 10:40PM0.50m | 10:59AM0.34m | 11:13PM0.38m | 11:26AM0.45m | 11:46PM0.30m | ||||||||
5:13 | — | — | 5:15 | — | — | 5:16 | — | — | 5:16 | — | — | 5:16 | — | — | 5:18 | — | — | 5:18 | — | — | |
— | 5:58 | — | — | 5:57 | — | — | 5:54 | — | — | 5:53 | — | — | 5:52 | — | — | 5:51 | — | — | 5:49 | — | |
mm | 7 | 7 | 3 | 1 | 4 | 5 | 3 | 3 | 16 | 3 | 2 | 2 | 1 | — | — | — | — | — | — | 1 | 1 |
Temp °C | 27 | 27 | 27 | 28 | 28 | 27 | 29 | 28 | 23 | 21 | 22 | 22 | 21 | 22 | 23 | 25 | 25 | 24 | 27 | 27 | 26 |
Feels °C | 25 | 26 | 28 | 30 | 31 | 29 | 28 | 29 | 24 | 19 | 21 | 23 | 22 | 25 | 27 | 28 | 28 | 27 | 30 | 30 | 30 |
Swell 1 Height (m) Direction Period (s) | E 8 | E 8 | S 9 | SSE 9 | SSE 9 | E 8 | NE 9 | NE 8 | S 9 | S 8 | S 8 | S 8 | S 8 | S 8 | NE 6 | E 14 | E 13 | E 13 | SSE 9 | SE 8 | SE 10 |
324 | 191 | 961 | 627 | 484 | 23 | 19 | 11 | 398 | 163 | 104 | 60 | 54 | 40 | 26 | 134 | 128 | 128 | 55 | 84 | 204 | |
Swell 2 Height (m) Direction Period (s) | ESE 11 | E 18 | E 8 | E 8 | E 8 | SE 10 | E 17 | E 16 | SE 11 | ESE 15 | ESE 15 | ESE 14 | E 14 | E 14 | E 14 | ESE 9 | SE 9 | ESE 8 | E 13 | E 13 | E 12 |
12 | 6 | 111 | 46 | 51 | 15 | 23 | 21 | 18 | 42 | 72 | 67 | 106 | 100 | 136 | 32 | 38 | 48 | 86 | 123 | 75 | |
Swell 3 Height (m) Direction Period (s) | ESE 11 | — | SE 10 | E 16 | ESE 10 | NNE 9 | ESE 10 | E 16 | ESE 16 | SE 9 | SE 10 | SE 9 | SE 10 | SE 10 | S 7 | S 7 | S 7 | SSW 7 | E 8 | ESE 10 | ENE 6 |
12 | — | 27 | 5 | 10 | 8 | 10 | 46 | 49 | 14 | 14 | 14 | 23 | 23 | 28 | 15 | 8 | 9 | 35 | 32 | 3 | |
Wind waves Height (m) Direction Period (s) | S 9 | S 9 | S 9 | — | S 9 | S 8 | S 8 | S 9 | NE 8 | NE 7 | ENE 7 | ENE 6 | NE 6 | NE 5 | — | NE 6 | ENE 3 | ENE 4 | ENE 6 | — | — |
1299 | 1553 | 1273 | — | 649 | 513 | 703 | 856 | 267 | 167 | 165 | 137 | 46 | 35 | — | 17 | 7 | 9 | 12 | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 84 | 88 | 86 | 57 | 23 | 88 | 554 | 71 | 110 | 51 | 51 | 22 | 0 | 0 | 0 | 0 | 56 | 0 | 0 | 9 | 9 |
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.










