Surf Forecasts:
Rock Island surf forecast from 23 Jul 2026:
- Best quality surf: Monday 27 Jul, 3AM (local time) - 1ft (0.3m), 10s period, SE swell with offshore winds.
- Most powerful swell: Tuesday 28 Jul, 12AM (local time) - 1.5ft (0.5m), 8s period, S swell with 34 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 3AM (local time) - 1ft (0.3m), 10s 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 Monday (Jul 27) at 3AM. The primary swell is predicted to be 0.2m and 14s period with a secondary swell of 0.3m and 9s. Another secondary swell of 0.3m and 10s is also forecast. Another secondary swell of 0.2m and 3s is also forecast. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Rock Island in the next 16 days are 0.5m 8s and forecast to arrive on Tuesday (Jul 28) 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 0.2m 5s period and expected on Wednesday (Jul 29) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Mon 27th Jul) | 1ft (0.3m) 10s |
| Best Surf | 3AM (Mon 27th Jul) | 1ft (0.3m) 10s |
| Most Powerful | 12AM (Tue 28th Jul) | 1.5ft (0.5m) 8s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Alright, surfers, Rusty here. Let’s break down Rock Island for the next couple of weeks.
I gotta be honest, the first week and a half is a total bummer. We’re looking at a long, flat period with nothing worth paddling out for. The wave energy is super weak, mostly in the teens and twenties, and the swell is coming from awkward directions. From now until the start of August, you’re better off doing something else. There’s just no surf on offer.
But don’t lose hope, because the long-range forecast is finally showing a light at the end of the tunnel. Tuesday morning, August 4th, is the standout. A solid 3ft south-east groundswell is forecast to hit, packing a serious 541 units of energy. The water is sitting at about 81°F, which is a touch warmer than usual for this time of year, so it’ll be nice and warm.
The real key is the wind: it’s calling for glassy conditions. That’s about as good as it gets. When you get a 3ft SE swell with zero wind, Rock Island’s reef (Big Island) will be perfect. This is a long-period swell at 16 seconds, so it’s a proper groundswell with plenty of power. The sets will be spaced out, making the paddle out easier, and the waves will have some real shape. It’s a beginner-friendly spot, so with a 3ft swell, it’s a great, manageable wave for most. The crowds can be *sometimes* an issue, so on a Tuesday morning with clean conditions, you might see a few others out there.
The following morning, Wednesday, August 5th, is a good backup option. The swell drops to a still fun 2ft from the ESE, but we’ll have a clean offshore breeze from the NE at 15 mph. The energy is still strong at 238 units, and the period is a lovely 16 seconds. It won’t be as perfect as Tuesday, but it’s a solid, clean option for a morning session.
So, here’s the takeaway: the next week is a total flat spell. Don’t waste your time. But if you can wait for the morning of Tuesday, August 4th, that’s your window. With glassy conditions and that 3ft SE groundswell, it’ll be worth the wait.
Stay stoked,
Rusty
Short Range ForecastHeavy rain (total 23mm), heaviest during Sat night. Warm (max 29°C on Thu night, min 24°C on Sat night). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 34mm), heaviest during Mon night. Warm (max 28°C on Sun night, min 23°C on Mon night). Wind will be generally light. | ||||||||||||||||||
Friday 24 | Saturday 25 | Sunday 26 | Monday 27 | Tuesday 28 | Wednesday 29 | ||||||||||||||
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) | SSE 10 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SSE 15 | SE 15 | SE 11 | SE 11 | SE 10 | SE 10 | S 8 | SSW 9 | S 6 | SSW 8 | SSW 6 | SSW 8 | SSW 8 |
Wave Graph  | |||||||||||||||||||
 kJ | 12 | 12 | 11 | 18 | 15 | 15 | 22 | 8 | 18 | 20 | 16 | 16 | 34 | 15 | 18 | 24 | 8 | 13 | 6 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | on | cross | cross-off | cross-on | cross-off | on | on | cross-off | off | on | cross-off | off | cross-off | cross-off | cross-off | on | cross-on |
High Tide | 10:43PM1.38m | 1:49PM1.13m | 11:30PM1.38m | 3:34PM1.21m | 00:29AM1.39m | 4:34PM1.30m | 1:35AM1.40m | 5:13PM1.37m | 2:38AM1.44m | 5:46PM1.42m | 3:36AM1.48m | 6:14PM1.45m | |||||||
Low Tide | 6:22AM0.44m | 5:30PM1.04m | 7:33AM0.35m | 7:05PM1.13m | 8:36AM0.25m | 8:38PM1.16m | 9:30AM0.16m | 9:45PM1.13m | 10:17AM0.10m | 10:34PM1.08m | 11:00AM0.06m | 11:15PM1.00m | |||||||
 |  | |  |  | | | |  | | |  | |  | | | | |  | |
 | — | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — | 4:46 | — | — | 4:46 | — | — | 4:47 | — | — |
 | 6:52 | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — |
mm | — | — | — | 3 | 2 | 2 | 15 | — | 1 | 13 | 1 | — | 15 | — | — | 5 | — | — | — |
Temp °C | 29 | 28 | 28 | 27 | 28 | 28 | 27 | 27 | 28 | 28 | 28 | 28 | 27 | 26 | 28 | 24 | 25 | 26 | 25 |
Feels °C | 33 | 31 | 30 | 31 | 33 | 31 | 31 | 29 | 30 | 32 | 31 | 31 | 31 | 27 | 31 | 26 | 28 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | S 5 | S 7 | SSE 9 | SE 11 | SE 10 | SE 10 | SSE 3 | SE 15 | SE 11 | S 9 | SSW 8 | SSW 8 | S 8 | SSW 6 | SSW 9 | SSW 8 | SSW 6 | SSW 8 | SSW 8 |
| kJ | 2 | 4 | 8 | 18 | 15 | 15 | 2 | 8 | 18 | 14 | 14 | 13 | 34 | 12 | 15 | 24 | 8 | 13 | 6 |
Swell 2 Height (m) Direction Period (s) | SSE 10 | SSE 9 | SE 17 | SE 16 | SE 16 | SE 16 | SE 10 | SE 11 | SE 15 | SE 11 | SE 10 | SE 10 | SE 10 | SSW 9 | SSE 10 | SE 10 | SSW 8 | SE 9 | SE 9 |
| kJ | 9 | 8 | 11 | 10 | 10 | 10 | 15 | 5 | 8 | 18 | 16 | 16 | 16 | 15 | 10 | 4 | 6 | 3 | 3 |
Swell 3 Height (m) Direction Period (s) | SE 18 | SE 18 | SE 11 | S 7 | — | S 7 | SSE 15 | SE 9 | S 9 | SSE 14 | SE 14 | SE 14 | SE 13 | SSE 10 | SE 13 | SE 13 | SE 10 | SE 12 | SE 12 |
| kJ | 12 | 12 | 5 | 1 | — | 1 | 22 | 3 | 2 | 20 | 8 | 8 | 7 | 9 | 7 | 7 | 4 | 6 | 6 |
Wind waves Height (m) Direction Period (s) | — | — | S 2 | SSE 3 | — | SSE 3 | — | SSE 4 | SSE 3 | S 3 | — | S 3 | — | — | S 6 | — | — | — | S 3 |
| kJ | — | — | 1 | 1 | — | 3 | — | 1 | 1 | 1 | — | 2 | — | — | 18 | — | — | — | 1 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 51 | 74 | 18 | 38 | 16 | 51 | 51 | 18 | 76 | 7 | 16 | 16 | 51 | 51 | 0 | 38 | 51 | 18 | 54 |
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.
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