
Surf Forecasts:
Onjuku surf forecast from 20 Jul 2026:
- Best quality surf: Thursday 23 Jul, 6AM (local time) - 2.5ft (0.8m), 10s period, E swell with glassy winds.
- Most powerful swell: Monday 20 Jul, 9PM (local time) - 4ft (1.2m), 11s period, E swell with 335 kJ wave energy.
- Next surfable swell (1★+): Thursday 23 Jul, 6AM (local time) - 2.5ft (0.8m), 10s 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 Thursday (Jul 23) at 6AM. The primary swell is predicted to be 0.8m and 10s period with a secondary swell of 0.4m and 5s. Another secondary swell of 0.6m and 5s 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 1.2m 11s and forecast to arrive on Monday (Jul 20) at 9PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 4s period and expected on Friday (Jul 24) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Thu 23rd Jul) | 2.5ft (0.8m) 10s |
| Best Surf | 6AM (Thu 23rd Jul) | 2.5ft (0.8m) 10s |
| Most Powerful | 9PM (Mon 20th Jul) | 4ft (1.2m) 11s |
Table - best surf conditions forecast for Onjuku over the next 16 days.
The Lowdown
Alright folks, Rusty here with a look at what’s coming up for Onjuku. It’s a bit of a slow start, but there’s some real promise further out if you’re patient.
The first week is pretty flat and messy. We’ve got a stretch from Monday the 20th through to Sunday the 26th with hardly anything worth paddling out for. The wind is a persistent cross-onshore, and the swell is small, weak, and wonky. The combined wave energy is low, stuck in the double digits or low triple digits (148 to 163), so it’s going to be a lot of groveling in choppy water. The water temp is sitting at 78°F, which is bang on average for this time of year, so at least it’s warm out there.
The first real glimmer of hope shows up on Thursday the 23rd morning. The wind swings NE, going cross-offshore, and the surf is clean but tiny. We’re talking about 3ft of swell from the east with a 10-second period and energy of 145. It’s surfable, but it’s strictly for the longboard or the foiler. Still, it’s a welcome change from the junk that came before.
Things stay quiet and small until we hit Tuesday the 28th. That’s when the ocean wakes up. The morning sees a jump to 6ft from the south with a 14-second period, and the energy surges to 1242. The wind is a cross-onshore, which makes it a bit lumpy, but the power is there. Then Tuesday afternoon is the standout of the first half: glassy conditions, 4ft from the SSW, and a 14-second period. The energy is 996, and the wind is dead calm. It’s going to be clean, but the wave height is more mellow—perfect for intermediate crew looking to score some smooth, lined-up waves without the chaos.
Wednesday the 29th sees the swell push up to 6ft to 7ft with a 15-second period, but the wind gets messy again, cross to cross-onshore. The energy is high (1488 to 1703), but the surface won’t be as pretty as Tuesday afternoon. Thursday the 30th morning is the real gem for the experienced surfers. We’ve got 7ft of clean SSW swell, glassy conditions, and a 15-second period. The energy is 1633. This is the kind of morning where you want to be first in the water. The waves will have serious push and juice, but the size and the long period (over 15 seconds) mean it’s going to be a bit lully and might close out on the beach. It’s best for those who know what they’re doing.
Friday the 31st gets even bigger. By afternoon, the swell hits 10ft from the SSW with a 16-second period and a massive energy of 5464. That’s big, powerful, and very long-period groundswell. The wind is a gentle cross-onshore, so it won’t be perfect, but for the big-wave chargers, it’s on. This is expert-only territory. The long period will make it tricky at the beach, with long waits between sets, but the energy is undeniable.
The first weekend of August (the 1st and 2nd) gets blown out hard by fresh cross-shore and cross-onshore winds, dropping the quality right back down. The 3rd and 4th of August see the swell settle back to 3ft to 4ft, with cleaner cross-offshore winds on the 4th, but the energy is moderate and the size is small.
The best bet: If you can time it, Tuesday the 28th afternoon for clean, glassy waves in the 4ft range. For the experienced crew, Thursday the 30th morning is the one to circle—7ft, glassy, and powerful. The big swell on Friday the 31st is a wildcard for the brave.
Rusty out.
Short Range ForecastMostly dry. Warm (max 29°C on Tue morning, min 25°C on Mon night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 12mm), heaviest on Fri night. Warm (max 28°C on Thu morning, min 23°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | |||||||||||||||
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) | E 9 | E 8 | E 11 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 9 | E 9 | E 9 | SE 11 | SE 16 | SE 16 | SE 16 | SE 15 | SE 11 | SE 10 | S 11 |
Wave Graph | |||||||||||||||||||||
119 | 116 | 329 | 257 | 247 | 196 | 196 | 156 | 121 | 113 | 81 | 80 | 57 | 57 | 66 | 65 | 63 | 57 | 55 | 65 | 64 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross-off | cross | cross-on | on | on |
High Tide | 8:32PM1.33m | 9:07AM1.04m | 8:57PM1.32m | 10:41AM0.95m | 9:26PM1.31m | 10:06PM1.28m | 11:05PM1.26m | 4:30PM1.13m | 00:24AM1.25m | 4:42PM1.19m | 1:35AM1.28m | ||||||||||
Low Tide | 2:01PM0.57m | 3:11AM0.58m | 2:24PM0.72m | 4:14AM0.54m | 2:41PM0.85m | 5:28AM0.50m | 6:45AM0.44m | 7:51AM0.37m | 7:16PM1.10m | 8:43AM0.30m | 8:40PM1.07m | ||||||||||
4:37 | — | — | 4:37 | — | — | 4:39 | — | — | 4:39 | — | — | 4:39 | — | — | 4:41 | — | — | 4:41 | — | — | |
— | 6:51 | — | — | 6:50 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:47 | — | — | 6:46 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | 3 | 5 | — | 3 | 1 | — | — | 1 |
Temp °C | 28 | 28 | 26 | 29 | 29 | 26 | 29 | 29 | 27 | 28 | 28 | 27 | 26 | 24 | 24 | 25 | 25 | 24 | 26 | 26 | 26 |
Feels °C | 32 | 30 | 29 | 32 | 31 | 30 | 33 | 32 | 31 | 31 | 32 | 31 | 28 | 26 | 27 | 27 | 27 | 27 | 28 | 27 | 28 |
Swell 1 Height (m) Direction Period (s) | E 9 | E 8 | E 11 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | E 9 | E 9 | E 9 | E 9 | E 8 | E 8 | E 8 | E 8 | E 6 | E 6 | E 5 |
119 | 116 | 329 | 257 | 247 | 196 | 196 | 156 | 121 | 113 | 81 | 80 | 57 | 56 | 35 | 35 | 51 | 48 | 26 | 26 | 20 | |
Swell 2 Height (m) Direction Period (s) | S 7 | E 14 | SSE 8 | SSW 4 | SSE 8 | SSE 8 | SSW 4 | SSE 7 | SSE 10 | SSW 5 | SSW 6 | SE 10 | SE 9 | SE 11 | SE 10 | SE 10 | SE 10 | SE 10 | SE 11 | SE 10 | SE 10 |
25 | 59 | 13 | 6 | 12 | 6 | 8 | 5 | 10 | 7 | 12 | 24 | 22 | 57 | 54 | 48 | 49 | 50 | 55 | 65 | 51 | |
Swell 3 Height (m) Direction Period (s) | S 7 | SSE 7 | SE 11 | SSE 8 | SE 11 | ESE 11 | SSE 8 | SE 11 | SSE 7 | SE 10 | SE 10 | SSW 5 | SE 18 | SE 17 | SE 16 | SE 16 | SE 16 | SE 15 | E 8 | E 8 | S 11 |
4 | 4 | 5 | 13 | 19 | 12 | 6 | 5 | 5 | 25 | 25 | 5 | 49 | 43 | 66 | 65 | 63 | 57 | 20 | 19 | 64 | |
Wind waves Height (m) Direction Period (s) | — | SSW 3 | SSW 4 | — | SSW 4 | SSW 4 | SW 5 | SSW 4 | SSW 4 | — | — | NE 3 | NE 4 | NE 4 | ENE 4 | ENE 4 | NE 4 | — | — | S 3 | S 4 |
— | 9 | 5 | — | 11 | 6 | 21 | 10 | 7 | — | — | 2 | 9 | 6 | 10 | 6 | 3 | — | — | 2 | 15 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 9 | 17 | 17 | 9 | 17 | 9 | 9 | 17 | 9 | 0 | 0 | 0 | 56 | 240 | 40 | 0 | 56 | 9 | 9 | 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.










