Surf Forecasts:
Rock Island surf forecast from 17 Jul 2026:
- Most powerful swell: Wednesday 22 Jul, 12AM (local time) - 3.5ft (1.0m), 5s period, SW swell with 47 kJ wave energy.
Best Forecast Surf Conditions for Rock Island this week:
The most powerful waves expected at Rock Island in the next 16 days are 1.0m 5s and forecast to arrive on Wednesday (Jul 22) at 12AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 3s period and expected on Thursday (Jul 23) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 12AM (Wed 22nd Jul) | 3.5ft (1.0m) 5s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Alright, Rusty here. Let's talk about what's cookin' at Rock Island.
The start is a total bust. We're looking at a solid 10 days of nothing. Tiny, weak, wind-blown slop. The water's about 77°, normal for this time of year. Don't even think about it.
The first real pulse hits on July 27th. A south swell pushes to about 5ft, but it's got onshore wind messing it up. The energy is there (2112, moderate), but it's a marginal call at best. Not worth the effort.
The day to circle is Wednesday, July 29th. The wind finally plays nice with a moderate offshore breeze from the NE. That cleans up a 4-5ft SSW swell. The energy is a solid 604 (moderate), and the wave comment says "expect very good surf conditions." The swell period is 12 seconds, so it's a proper groundswell. For a reef break, that's gonna be smooth and lined up. The spot is fairly consistent, and crowds are a possibility, so get your timing right.
Thursday the 30th still has a clean 4ft wave in the morning, but it goes south by the afternoon. Friday the 31st of July sees a bigger 8ft SSW swell, but it's a short period (8 seconds) and the wind is cross-offshore. That's getting into expert-only territory and the short period means it'll be a bit crumbly.
So, the 29th of July is your one clear shot. Everything else is either flat or blown out after that.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri morning. Warm (max 27°C on Fri morning, min 25°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 4mm), mostly falling on Wed night. Warm (max 29°C on Wed morning, min 27°C on Mon morning). Wind will be generally light. | ||||||||||||||||||||
Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | |||||||||||||||
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) | SE 10 | S 4 | SSE 9 | SE 9 | SE 8 | SE 8 | SE 8 | S 3 | S 8 | SSE 9 | S 4 | SSW 4 | SW 4 | SSW 4 | SW 5 | SSW 6 | SSW 6 | SE 11 | SSE 10 | SSE 10 | SSE 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 15 | 6 | 8 | 12 | 11 | 10 | 9 | 11 | 5 | 8 | 12 | 13 | 9 | 17 | 47 | 12 | 11 | 4 | 10 | 10 | 10 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | on | on | on | on | on | on | on | on | on | on | on | on | on | on | off | off | cross-off | off |
High Tide | 7:41PM1.45m | 6:25AM1.48m | 8:09PM1.43m | 7:14AM1.43m | 8:36PM1.42m | 8:05AM1.36m | 9:04PM1.41m | 9:03AM1.27m | 9:33PM1.40m | 10:14AM1.18m | 10:05PM1.39m | 11:48AM1.12m | 10:43PM1.38m | ||||||||
Low Tide | 12:43PM0.07m | 00:59AM0.86m | 1:20PM0.16m | 1:40AM0.79m | 1:55PM0.29m | 2:24AM0.71m | 2:31PM0.43m | 3:12AM0.65m | 3:07PM0.59m | 4:07AM0.58m | 3:45PM0.75m | 5:11AM0.52m | 4:29PM0.91m | ||||||||
 |  |  | |  | | | |  | | | | | | | | |  | | | | |
 | 4:39 | — | — | 4:39 | — | — | 4:39 | — | — | 4:41 | — | — | 4:41 | — | — | 4:41 | — | — | 4:43 | — | — |
 | — | 6:55 | — | — | 6:54 | — | — | 6:54 | — | — | 6:53 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — |
mm | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 4 | — | 1 | — |
Temp °C | 27 | 27 | 26 | 27 | 27 | 26 | 27 | 27 | 26 | 28 | 28 | 27 | 28 | 28 | 28 | 29 | 29 | 27 | 29 | 30 | 26 |
Feels °C | 31 | 29 | 28 | 29 | 29 | 28 | 28 | 28 | 27 | 30 | 30 | 28 | 31 | 30 | 30 | 33 | 33 | 31 | 30 | 31 | 27 |
Swell 1 Height (m) Direction Period (s) | SSW 8 | SSW 8 | SSE 9 | SSE 4 | SE 8 | SE 8 | SE 8 | SE 12 | SSE 7 | SSE 9 | SE 11 | SSE 8 | SSW 4 | SE 8 | SSW 5 | SSW 6 | SE 11 | S 4 | SSE 10 | SSE 10 | SSE 10 |
| kJ | 6 | 6 | 8 | 3 | 11 | 10 | 9 | 6 | 5 | 8 | 5 | 7 | 6 | 3 | 25 | 12 | 5 | 2 | 10 | 10 | 10 |
Swell 2 Height (m) Direction Period (s) | SE 10 | SE 9 | SSW 8 | SE 9 | S 9 | S 8 | S 8 | — | S 8 | S 7 | SSE 8 | S 7 | SSE 8 | E 11 | SE 8 | SE 8 | SE 7 | SE 11 | S 4 | S 8 | — |
| kJ | 4 | 3 | 6 | 12 | 2 | 1 | 5 | — | 5 | 4 | 7 | 1 | 6 | 2 | 2 | 2 | 2 | 4 | 2 | 1 | — |
Swell 3 Height (m) Direction Period (s) | SE 10 | E 8 | E 10 | S 7 | S 8 | S 8 | E 12 | S 8 | S 9 | E 11 | ESE 11 | E 11 | E 11 | ESE 11 | SE 11 | SE 11 | SE 8 | SE 8 | S 8 | S 7 | SE 8 |
| kJ | 15 | 1 | 2 | 1 | 1 | 1 | 3 | 5 | 2 | 3 | 12 | 2 | 2 | 12 | 5 | 4 | 2 | 2 | 1 | 1 | 3 |
Wind waves Height (m) Direction Period (s) | SSE 4 | S 4 | SSE 4 | — | S 4 | SSE 3 | S 4 | S 3 | S 4 | S 3 | S 4 | SSW 4 | SW 4 | SSW 4 | SW 5 | — | SSW 6 | — | — | S 4 | ESE 3 |
| kJ | 2 | 6 | 5 | — | 5 | 2 | 1 | 11 | 4 | 1 | 12 | 13 | 9 | 17 | 47 | — | 11 | — | — | 2 | 1 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 64 | 145 | 77 | 77 | 64 | 64 | 18 | 76 | 76 | 77 | 77 | 92 | 76 | 534 | 12 | 18 | 76 | 55 | 51 | 514 | 51 |
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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