
Surf Forecasts:
Rock Island surf forecast from 30 Jul 2026:
- Best quality surf: Thursday 6 Aug, 12AM (local time) - 11ft (3.5m), 16s period, SSE swell with cross-offshore winds.
- Most powerful swell: Thursday 6 Aug, 12AM (local time) - 11ft (3.5m), 16s period, SSE swell with 6,000 kJ wave energy.
- Next surfable swell (1★+): Sunday 2 Aug, 12AM (local time) - 1ft (0.3m), 17s period with SE swell.
Best Forecast Surf Conditions for Rock Island this week:
The surf forecast for Rock Island over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Aug 02) at 12AM. The primary swell is predicted to be 0.3m and 17s period with a secondary swell of 0.3m and 6s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Rock Island in the next 16 days are 3.5m 16s and forecast to arrive on Thursday (Aug 06) at 12AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Monday (Aug 03) at 9AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Sun 2nd Aug) | 1ft (0.3m) 17s |
| Best Surf | 12AM (Thu 6th Aug) | 11ft (3.5m) 16s |
| Most Powerful | 12AM (Thu 6th Aug) | 11ft (3.5m) 16s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it.
The next few days are a slow start, but don’t write it off just yet. We’ve got a solid run of groundswell building from the south, and if you’re patient, there’s a window of proper waves coming.
First up, we’re looking at Rock Island. Friday the 31st through Saturday the 1st are pretty much a write-off. Tiny, weak swell with poor conditions. The energy is weak (29 to 31), and the best you’ll get is a glassy morning with a 1ft swell on Saturday, but it’s coming from the wrong direction and has no push. Not worth paddling out for.
Sunday the 2nd shows a slight pulse. A 1ft swell from the ESE with a long 16-second period shows up. The combined energy jumps to 104 (moderate), and it’s glassy in the morning. Surfable, but ordinary. Still, a morning session might get you a few.
Now, Monday the 3rd of August is where it starts to get interesting. A 3ft SE groundswell with a 17-second period arrives, and we’ve got clean offshore NE wind at 12 mph. This is a proper combo. The energy is 411 (moderate), and conditions are moderate offshore and clean. This is a good sign of things to come.
Tuesday the 4th of August is a standout. The swell jumps to 5ft from the SE, still with that long 17-second period. The energy is 1995 (strong), and the wind is NE at 12 mph, offshore and clean. This is excellent surf for experienced surfers. The water temperature is about average for this time of year. The morning session is the pick here, with the best conditions. The afternoon sees 7ft, but the wind goes cross-off, and the score drops. Still, Tuesday morning is the one to circle.
Wednesday the 5th of August is proper. We’re talking 10ft of SSE groundswell, with a 17-second period. The energy is 4762 (very strong), and the wind is offshore NE at 12 mph. This is huge, powerful surf. For expert surfers only. The quality is absolutely on offer in the morning. The afternoon has the same size, but the wind goes cross, so it’s not as clean. Get it while it’s good.
Thursday the 6th of August is the peak. 10ft from the S, 16-second period, and the energy is 5632 (very strong). Gentle offshore NE wind at 9 mph. This is exceptional surf for expert surfers. The morning session is the best on offer in the entire forecast. It’s clean, powerful, and has that long, lined-up groundswell feel. The afternoon is a write-off with onshore wind.
By Friday the 7th, the swell drops to 8ft, but the wind is cross-on, so it’s marginal. The weekend of the 8th and 9th sees the swell fade, with a glassy 6ft on Saturday morning but the wind is onshore by the afternoon. Sunday the 9th is small and clean, but not a standout.
The second week, from the 10th of August onward, is quiet. Monday the 10th has a little 3ft pulse with offshore wind, but the energy is low (233). After that, it’s all small, weak, and mostly clean but not surf-worthy. Tuesday the 11th through to the 15th is a long stretch of tiny waves, mostly under 2ft, with poor to ordinary conditions. A gap of several days with no real recommendations.
The standout windows are Tuesday the 4th morning, and Wednesday and Thursday the 5th and 6th mornings. The absolute best is Thursday morning the 6th. That’s the one you want to clear your schedule for.
Rusty.
Short Range ForecastMostly dry. Warm (max 31°C on Sun morning, min 27°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 30°C on Wed afternoon, min 23°C on Mon night). Wind will be generally light. | ||||||||||||||||||
Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | Wednesday 5 | ||||||||||||||
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 6 | S 6 | S 6 | SSW 6 | SSW 7 | SE 18 | SE 17 | ESE 16 | SE 15 | ESE 16 | SE 17 | SE 18 | SE 18 | SE 17 | SE 17 | SE 16 | SSE 17 | SSE 17 | SSE 16 |
Wave Graph | |||||||||||||||||||
21 | 20 | 21 | 13 | 9 | 12 | 46 | 99 | 104 | 162 | 410 | 600 | 1162 | 1415 | 2471 | 2776 | 4762 | 5593 | 6000 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | off | on | cross-on | glassy | on | glassy | glassy | on | off | off | off | off | off | cross-off | off | off | cross | cross-off |
High Tide | 5:16AM1.53m | 7:07PM1.47m | 6:03AM1.53m | 7:32PM1.46m | 6:50AM1.50m | 7:56PM1.45m | 7:38AM1.44m | 8:21PM1.45m | 8:29AM1.35m | 8:48PM1.44m | 9:29AM1.26m | 9:16PM1.43m | |||||||
Low Tide | 11:52PM0.91m | 12:16PM0.11m | 00:29AM0.82m | 12:51PM0.19m | 1:07AM0.73m | 1:26PM0.30m | 1:46AM0.65m | 1:59PM0.44m | 2:29AM0.59m | 2:32PM0.59m | 3:17AM0.54m | 3:04PM0.75m | |||||||
— | 4:48 | — | — | 4:48 | — | — | 4:50 | — | — | 4:50 | — | — | 4:52 | — | — | 4:52 | — | — | |
6:46 | — | 6:45 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 29 | 30 | 30 | 28 | 29 | 29 | 29 | 31 | 30 | 27 | 27 | 27 | 25 | 27 | 29 | 25 | 28 | 30 | 26 |
Feels °C | 33 | 33 | 31 | 31 | 33 | 31 | 33 | 36 | 32 | 28 | 27 | 26 | 24 | 26 | 28 | 24 | 29 | 32 | 28 |
Swell 1 Height (m) Direction Period (s) | S 6 | S 6 | SE 9 | SSW 6 | SSW 7 | SE 15 | SE 17 | ESE 16 | SE 15 | ESE 16 | SE 17 | SE 18 | SE 18 | SE 17 | SE 17 | SE 16 | SSE 17 | SSE 17 | SSE 16 |
21 | 20 | 3 | 13 | 9 | 8 | 46 | 99 | 104 | 162 | 410 | 600 | 1162 | 1415 | 2471 | 2776 | 4762 | 5593 | 6000 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | SE 9 | S 8 | SE 10 | SE 10 | SE 18 | SSW 6 | S 5 | SSE 9 | SSE 9 | S 8 | S 8 | E 14 | SE 20 | E 13 | — | — | — | — |
3 | 3 | 1 | 4 | 4 | 12 | 6 | 2 | 8 | 8 | 1 | 1 | 4 | 580 | 14 | — | — | — | — | |
Swell 3 Height (m) Direction Period (s) | SE 12 | SE 12 | S 11 | S 8 | SE 15 | SE 9 | SSE 9 | SE 9 | SSE 10 | S 9 | — | — | — | — | — | — | — | — | — |
6 | 6 | 3 | 1 | 9 | 3 | 8 | 3 | 9 | 2 | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | S 6 | — | — | SSW 6 | — | — | S 5 | ENE 2 | NE 3 | — | — | — | — | — | — | — | — |
— | — | 21 | — | — | 8 | — | — | 4 | 1 | 2 | — | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 38 | 16 | 77 | 54 | 55 | 77 | 0 | 0 | 54 | 8 | 0 | 38 | 4 | 0 | 6 | 0 | 0 | 6 | 0 |
Best forecast wave conditions in Kanagawa | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
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Information about the Rock Island Surf forecast
The above surf forecast table for Rock Island provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Rock Island can be found by selecting the local surf guide option on the grey menu. Our Rock Island 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 (Rock Island) 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 Rock Island 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.
Rock Island is 3 km (2 miles) from the city of Kamakura. If you plan a holiday in Kanagawa, look for hotels and other accommodation in Kamakura. Kamakura has rooms for a wide range of budgets as well as car hire and transport links.











