
Surf Forecasts:
Rock Island surf forecast from 1 Aug 2026:
- Best quality surf: Wednesday 5 Aug, 3PM (local time) - 8ft (2.5m), 16s period, SSE swell with offshore winds.
- Most powerful swell: Wednesday 5 Aug, 3PM (local time) - 8ft (2.5m), 16s period, SSE swell with 3,745 kJ wave energy.
- Next surfable swell (1★+): Sunday 2 Aug, 3AM (local time) - 0.5ft (0.2m), 18s period with ESE 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 3AM. The primary swell is predicted to be 0.2m and 18s period with a secondary swell of 0.4m and 6s. Another secondary swell of 0.2m and 14s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Rock Island in the next 16 days are 2.5m 16s and forecast to arrive on Wednesday (Aug 05) at 3PM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 4s period and expected on Wednesday (Aug 05) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Sun 2nd Aug) | 0.5ft (0.2m) 18s |
| Best Surf | 3PM (Wed 5th Aug) | 8ft (2.5m) 16s |
| Most Powerful | 3PM (Wed 5th Aug) | 8ft (2.5m) 16s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s on offer at Rock Island for the next couple of weeks.
The good news is, we’ve got a solid run of surf coming, but you’ve gotta be patient. The first few days are a bit of a write-off, with some small, weak leftovers on Sunday the 2nd. The swell energy is low (107) and the wind is messy, so it’s not worth paddling out for.
Things start to get interesting from Monday the 3rd. We’ve got a building southerly groundswell with a very long period of 19 seconds pushing in. The wave height is still small at 3 ft, but the energy is ramping up (615) and the wind is offshore and clean. It’s a bit marginal, but the signs are there.
The real standout kicks off on Wednesday the 5th of August. This is the one to circle. We’re looking at a solid 8 ft swell from the SSE, with a period of 16 seconds. The combined energy is pumping at 3745, and we’ve got a moderate offshore breeze from the NNE keeping things clean. The water temperature is about average for the time of year. This is proper, powerful groundswell, and it’s going to be breaking cleanly at Rock Island reef. This is for experienced surfers only – 8 ft is not for the faint-hearted. The morning of the 5th is also good, but the afternoon is the pick with the lighter winds.
Thursday the 6th keeps the quality going. Another 8 ft day, this time from the S, with a light cross-offshore breeze in the afternoon. The energy is still massive (3314), and it’s going to be clean. Friday the 7th morning is still firing with a 7 ft S swell, but the wind swings onshore in the afternoon, so get your session in early.
The swell drops off through the weekend, but Saturday the 8th is still a good option. The morning has a 5 ft SSW swell and offshore wind, but the afternoon is a real treat getting glassy conditions with a 5 ft SSW swell. That’s a great window for some fun, clean waves.
After that, the surf goes quiet for a long stretch. From the 9th of August right through, the swell drops to under 3 ft, and the energy fades. There’s a brief, tiny window on the 13th and 15th with some small waist-high waves and clean conditions, but it’s really just a chance to get wet if you’re desperate. The 15th morning has a glassy 3 ft SE swell, but it’s weak.
So, to wrap it up: The best surf of the whole 16-day window is Wednesday the 5th and Thursday the 6th of August. Big, powerful swell, clean offshore winds, and solid energy. It’s a reef break, so it’s gonna be a show. Get on it if you’ve got the skills.
Rusty.
Short Range ForecastMostly dry. Warm (max 32°C on Sun morning, min 23°C on Mon night). Winds increasing (calm on Sat night, fresh winds from the NE by Mon night). | Days 5-7 Weather SummaryLight rain (total 6mm), mostly falling on Thu night. Warm (max 30°C on Thu morning, min 23°C on Tue night). Winds decreasing (fresh winds from the NNE on Tue night, calm by Fri morning). | ||||||||||||||||||
Sunday 2 | Monday 3 | Tuesday 4 | Wednesday 5 | Thursday 6 | Friday 7 | ||||||||||||||
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) | SE 17 | ESE 16 | SE 15 | ESE 15 | SE 16 | SE 19 | SE 17 | SE 16 | SE 17 | SE 16 | SSE 16 | SSE 16 | SSE 16 | S 15 | S 16 | S 15 | S 15 | SSW 15 | SSW 14 |
Wave Graph | |||||||||||||||||||
46 | 99 | 104 | 148 | 258 | 614 | 861 | 1165 | 1712 | 2676 | 3278 | 3745 | 3175 | 2325 | 3314 | 2720 | 2206 | 1801 | 1259 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-off | cross-on | off | off | off | off | off | cross-off | off | off | off | off | off | cross-off | cross | cross-off | on | cross-off |
High Tide | 6:50AM1.50m | 7:56PM1.45m | 7:38AM1.44m | 8:21PM1.45m | 8:29AM1.35m | 8:48PM1.44m | 9:29AM1.26m | 9:16PM1.43m | 10:48AM1.17m | 9:49PM1.41m | 12:41PM1.13m | 10:30PM1.40m | |||||||
Low Tide | 1:07AM0.73m | 1:26PM0.30m | 1:46AM0.65m | 1:59PM0.44m | 2:29AM0.59m | 2:32PM0.59m | 3:17AM0.54m | 3:04PM0.75m | 4:14AM0.50m | 3:39PM0.90m | 5:21AM0.46m | 4:23PM1.04m | |||||||
— | 4:50 | — | — | 4:50 | — | — | 4:52 | — | — | 4:52 | — | — | 4:52 | — | — | 4:54 | — | — | |
6:45 | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 6 | — | — | — |
Temp °C | 28 | 32 | 31 | 26 | 25 | 26 | 24 | 26 | 27 | 24 | 25 | 27 | 25 | 30 | 30 | 27 | 29 | 30 | 26 |
Feels °C | 32 | 34 | 33 | 26 | 24 | 24 | 21 | 23 | 24 | 22 | 23 | 27 | 25 | 32 | 32 | 30 | 32 | 32 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 6 | ESE 16 | SE 15 | ESE 15 | SE 16 | SE 19 | SE 17 | SE 16 | SE 17 | SE 16 | SSE 16 | SSE 16 | SSE 16 | S 15 | S 16 | S 15 | S 15 | SSW 15 | SSW 14 |
11 | 99 | 104 | 148 | 258 | 614 | 861 | 1165 | 1712 | 2676 | 3278 | 3745 | 3175 | 2325 | 3314 | 2720 | 2206 | 1801 | 1259 | |
Swell 2 Height (m) Direction Period (s) | SE 17 | S 5 | SE 9 | SE 9 | SE 22 | S 8 | E 14 | — | E 13 | — | — | — | — | S 18 | — | ESE 11 | ESE 12 | ESE 11 | ESE 10 |
46 | 5 | 3 | 3 | 75 | 1 | 4 | — | 3 | — | — | — | — | 1080 | — | 12 | 13 | 12 | 122 | |
Swell 3 Height (m) Direction Period (s) | SE 9 | SE 9 | SE 7 | SE 4 | S 8 | — | — | — | — | — | — | — | — | — | — | — | — | — | SE 12 |
3 | 3 | 2 | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | 6 | |
Wind waves Height (m) Direction Period (s) | — | — | SSW 6 | NE 3 | NE 3 | NE 3 | NE 3 | NNE 3 | NE 4 | — | — | — | — | — | — | — | — | — | — |
— | — | 7 | 2 | 5 | 6 | 7 | 10 | 10 | — | — | — | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 8 | 54 | 4 | 38 | 145 | 491 | 491 | 491 | 491 | 552 | 0 | 0 | 0 | 0 | 12 | 0 | 64 | 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.











