Surf Forecasts:
Big Ben surf forecast from 18 Aug 2026:
- Best quality surf: Tuesday 25 Aug, 6AM (local time) - 10ft (3.0m), 16s period, SSE swell with cross-shore winds.
- Most powerful swell: Tuesday 25 Aug, 12PM (local time) - 10ft (3.0m), 16s period, SSE swell with 3,816 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 12AM (local time) - 1.5ft (0.5m), 9s period with E swell.
Best Forecast Surf Conditions for Big Ben this week:
The surf forecast for Big Ben over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 20) at 12AM. The primary swell is predicted to be 0.5m and 9s period with a secondary swell of 0.6m and 6s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Big Ben in the next 16 days are 3.0m 16s and forecast to arrive on Tuesday (Aug 25) at 12PM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Thu 20th Aug) | 1.5ft (0.5m) 9s |
| Best Surf | 6AM (Tue 25th Aug) | 10ft (3.0m) 16s |
| Most Powerful | 12PM (Tue 25th Aug) | 10ft (3.0m) 16s |
Table - best surf conditions forecast for Big Ben over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s have a proper look at the next couple of weeks for Big Ben. I’ll be straight with you: it’s a slow burner, then things get wild for a stretch before we finally catch a decent window. Don’t get too excited about the early days; you’ll be sitting on the beach for a while.
Right off the bat, the water’s sitting at about 80.9°, which is pretty much spot on for this time of year—nothing weird happening there.
The first week is grim, plain and simple. From Tuesday the 18th through to Friday the 21st, there’s barely a ripple. We’re talking ankle-biters around 1.3ft to 3ft, short-period slop, and the wind is mostly onshore or cross-onshore, messing up anything that tries to form. The energy is weak; values like 144 and 162 (combined swell energy) tell you there’s nothing substantial out there. It’s a write-off for a surf. You’d have more fun cleaning your board.
Then the weekend rolls in with a bit more pulse, but it’s still not worth paddling out for. Saturday the 22nd and Sunday the 23rd see the swell nudge up to around 3.3ft, but it’s straight cross-shore and there’s a risk of thunderstorms. The energy is creeping up—211, 254, 273—but the quality is just marginal. You’d be scratching for a shabby one.
Now, here’s where the story takes a turn. Monday the 24th of August sees a proper groundswell arrive. The period jumps to 16 seconds, a real long-period swell, and the size starts climbing. By Monday afternoon we’re looking at 7.2ft, but it’s getting cross-onshore and choppy. The energy jumps massively—1507 and then 2735—but the break just can’t hold it together.
And then it gets serious. Tuesday the 25th onwards, the ocean turns angry. The swell is predicted to be 9.8ft, then 11.5ft by Wednesday the 26th, and the period stays long at 15-16 seconds. The combined energy explodes—4063, 4680, 5646—this is strong to very strong wave energy. But here’s the catch: this break, Big Ben, is a beach/jetty setup, and it’s just going to be too big and unruly. The guidance says it’s “too big for this break.” For a beginner spot, this is dangerous. For experts, it’s still a washing machine. The wind turns onshore and howls at 25-30 km/h by Thursday the 27th, making it absolutely messy. The surf quality is poor, and it’s just a big, blown-out mess. Honestly, with that much swell and strong onshores, this setup looks more interesting for kite surfing than paddle surfing. You’d be mad to go out there on a board.
This theme continues into the next week. Friday the 28th is still huge, 8.2ft, but a strong breeze is whipping it into a choppy storm. Saturday the 29th sees the swell peak again at 13.1ft with a fresh cross-shore wind, but it’s still just too big for this spot. The energy is around 4500. This window, from the 25th to the 29th, is a full-on blank for clean waves at Big Ben.
But then, just when you think it’s all over, we get a glimpse of hope. Sunday the 30th of August, the wind swings around to the NNE, giving us a cross-offshore breeze. The swell drops to a still-chunky 6.6ft, but the direction shifts to the SSW, and the period is a solid 14 seconds. The energy is still strong at 2897. For the first time in days, it’s clean. This is the standout window, but it’s only for the morning. The forecast says “excellent surf conditions for experienced surfers.” This is your moment. The surf is going to be bigger than 5ft, so it’s not for beginners, and at 6.6ft, it’s solidly in the expert zone, but it’s rideable and clean.
Monday the 31st of August is a bit of a letdown after that. The swell stays around 5.2ft to 5.9ft, but the period drops a bit and it’s still cross-offshore. The energy is around 1500-1800, which is moderate, but the conditions are described as “clean.” There might be a few fun ones if you’re keen, but it’s not a patch on Sunday morning.
And then, the ocean loses its mind again. Tuesday the 1st of September, the swell jumps to 13.1ft with a 15-second period and the energy rockets to 7413. It’s clean, cross-offshore wind, but it’s just way too big for this break. Another one for the experts only
Short Range ForecastMostly dry. Warm (max 28°C on Tue morning, min 24°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 14mm), heaviest on Sun morning. Warm (max 28°C on Fri morning, min 25°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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) | ESE 8 | E 9 | E 9 | E 9 | SE 10 | E 9 | SE 11 | SE 11 | SE 11 | SE 11 | E 9 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | SE 14 | SSE 16 | SSE 16 | SSE 16 |
Wave Graph | |||||||||||||||||||||
107 | 73 | 54 | 39 | 49 | 39 | 43 | 57 | 57 | 58 | 87 | 94 | 146 | 192 | 233 | 190 | 115 | 357 | 1305 | 2479 | 3326 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | on | cross-on | on | glassy | on | on | cross | cross-on | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on |
High Tide | 7:24PM1.50m | 8:20AM1.27m | 7:46PM1.47m | 9:31AM1.15m | 8:09PM1.44m | 8:37PM1.39m | 9:26PM1.33m | 4:10PM1.33m | 00:01AM1.29m | 4:16PM1.41m | 1:46AM1.34m | ||||||||||
Low Tide | 1:17PM0.66m | 2:01AM0.49m | 1:39PM0.82m | 2:52AM0.50m | 1:53PM0.97m | 4:00AM0.52m | 5:40AM0.51m | 7:19AM0.44m | 8:35PM1.23m | 8:26AM0.35m | 9:17PM1.13m | ||||||||||
5:00 | — | — | 5:01 | — | — | 5:01 | — | — | 5:03 | — | — | 5:03 | — | — | 5:03 | — | — | 5:05 | — | — | |
— | 6:24 | — | — | 6:23 | — | — | 6:22 | — | — | 6:22 | — | — | 6:20 | — | — | 6:19 | — | — | 6:17 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 2 | 2 | 3 | 2 | 3 | 2 | — | — | — |
Temp °C | 28 | 27 | 25 | 28 | 28 | 25 | 28 | 27 | 25 | 28 | 28 | 25 | 28 | 28 | 26 | 28 | 28 | 26 | 28 | 28 | 25 |
Feels °C | 30 | 29 | 28 | 30 | 30 | 28 | 30 | 29 | 28 | 30 | 30 | 28 | 31 | 31 | 30 | 32 | 31 | 30 | 30 | 29 | 27 |
Swell 1 Height (m) Direction Period (s) | ESE 8 | E 9 | SE 6 | SE 6 | SE 6 | SE 6 | SE 6 | SE 6 | E 8 | SSW 9 | E 9 | E 10 | E 10 | E 10 | E 10 | E 10 | E 10 | SE 14 | SSE 16 | SSE 16 | SSE 16 |
107 | 73 | 33 | 23 | 28 | 26 | 25 | 15 | 48 | 45 | 87 | 94 | 146 | 192 | 233 | 190 | 115 | 357 | 1305 | 2479 | 3326 | |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 7 | E 9 | E 9 | E 9 | E 9 | SE 11 | SE 11 | SE 11 | E 7 | SSW 9 | SSW 10 | SSW 9 | SSW 9 | SSW 9 | S 5 | E 12 | E 12 | E 9 | E 12 | ESE 11 |
36 | 35 | 54 | 39 | 39 | 39 | 43 | 57 | 57 | 23 | 45 | 72 | 59 | 56 | 65 | 15 | 103 | 139 | 57 | 224 | 202 | |
Swell 3 Height (m) Direction Period (s) | SSW 8 | SE 10 | SE 10 | SE 10 | SE 10 | SE 10 | ENE 9 | ENE 9 | SSW 8 | SE 11 | SE 11 | SE 11 | SE 5 | SE 5 | SE 11 | SW 9 | S 4 | E 9 | E 12 | WSW 10 | SW 10 |
13 | 36 | 36 | 35 | 49 | 36 | 26 | 26 | 14 | 58 | 30 | 33 | 6 | 6 | 18 | 40 | 9 | 60 | 99 | 10 | 15 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | S 4 | SSW 4 | SSW 4 | SSW 4 | SSW 8 | SW 8 | SSW 8 |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | 9 | 28 | 14 | 5 | 46 | 32 | 45 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 30 | 30 | 30 | 22 | 30 | 0 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 35 | 114 | 30 | 30 |
Best forecast wave conditions in Chiba | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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Information about the Big Ben Surf forecast
The above surf forecast table for Big Ben provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Big Ben can be found by selecting the local surf guide option on the grey menu. Our Big Ben 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 (Big Ben) 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 Big Ben 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.
Big Ben is 3 km (2 miles) from Kawaguchi. If you plan a holiday in Chiba, look for hotels and other accommodation in Kawaguchi. Kawaguchi has rooms for a wide range of budgets as well as car hire and transport links.











