Surf Forecasts:
Rock Island surf forecast from 10 Jul 2026:
- Best quality surf: Sunday 12 Jul, 9AM (local time) - 5.5ft (1.7m), 16s period, SSW swell with glassy winds.
- Most powerful swell: Saturday 11 Jul, 9AM (local time) - 7ft (2.1m), 16s period, SSW swell with 2,368 kJ wave energy.
- Next surfable swell (1★+): Sunday 12 Jul, 9AM (local time) - 5.5ft (1.7m), 16s period with SSW 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 (Jul 12) at 9AM. The primary swell is predicted to be 1.7m and 16s period with a secondary swell of 0.4m and 10s. 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 2.1m 16s and forecast to arrive on Saturday (Jul 11) at 9AM. Winds are predicted to be onshore at the time the swell arrives.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9AM (Sun 12th Jul) | 5.5ft (1.7m) 16s |
| Best Surf | 9AM (Sun 12th Jul) | 5.5ft (1.7m) 16s |
| Most Powerful | 9AM (Sat 11th Jul) | 7ft (2.1m) 16s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
Alright, Rusty here. Let’s break down what’s on the menu for Rock Island.
We start with a solid pulse of long-period groundswell from the south. Friday morning (10 July) sees 5ft of clean S swell with a 15-second period, and the combined energy is a strong 1672. Light offshore wind from the south means it’ll be glassy. The water’s at 75°, which is a bit cooler than average for this time of year – about a degree off, so you’ll feel it. Saturday morning (11 July) bumps up to 7ft from the SSW, but the wind goes onshore and it gets messy. Crowds are possible here.
The real standout is Sunday morning (12 July). Glassy conditions, southwest wind at just 3 mph, and a 6ft SSW swell with a 16-second period. The combined energy is still strong at 1547, and conditions are rated excellent for experienced surfers. This is the best window – clean, lined-up reef waves with proper groundswell. If you’re confident on a reef, this is your call.
After that, the swell drops fast. Monday (13 July) is down to 3ft with clean conditions and a light offshore breeze, but the energy is weak (227). The rest of the week and into the next is a long stretch of small, poor surf. There’s nearly a week with nothing worth paddling out for – tiny waves, onshore wind, and low energy.
We get a little bump Thursday 23 July afternoon, with 4ft of S swell and a 12-second period, but the wind is onshore and conditions are marginal. Not worth the hype. Friday 24 July morning has a brief clean window at 2ft from the SSE with cross-offshore wind, but the energy is weak (200).
Don’t get your hopes up for the second week. The only real standout is that Sunday morning glass-off. Be there.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Sat night. Warm (max 25°C on Fri morning, min 23°C on Fri night). Winds decreasing (fresh winds from the S on Sat afternoon, calm by Sun morning). | Days 4-6 Weather SummaryMostly dry. Warm (max 29°C on Mon afternoon, min 24°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Friday 10 | Saturday 11 | Sunday 12 | Monday 13 | Tuesday 14 | Wednesday 15 | Thursday 16 | |||||||||||||||
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) | S 15 | S 16 | SSW 16 | SSW 16 | SSW 17 | SSW 16 | SSW 16 | SSW 15 | SSW 14 | SSW 12 | SSW 12 | SSW 11 | SSW 11 | SSW 10 | SSW 10 | S 10 | SSW 9 | SSW 9 | SSW 9 | SSE 11 | SSE 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1074 | 2141 | 2133 | 2368 | 2296 | 1697 | 1512 | 1079 | 467 | 220 | 206 | 109 | 91 | 85 | 102 | 47 | 28 | 27 | 8 | 12 | 80 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | on | on | on | on | glassy | on | on | off | cross-off | off | cross-off | on | on | on | on | on | on | on | glassy |
High Tide | 2:42PM1.15m | 00:30AM1.37m | 4:01PM1.24m | 1:22AM1.40m | 4:55PM1.32m | 2:17AM1.43m | 5:37PM1.38m | 3:10AM1.46m | 6:12PM1.43m | 4:01AM1.49m | 6:44PM1.45m | 4:50AM1.51m | 7:13PM1.45m | ||||||||
Low Tide | 6:45PM1.02m | 8:19AM0.28m | 8:06PM1.09m | 9:13AM0.17m | 9:17PM1.11m | 10:01AM0.08m | 10:13PM1.10m | 10:45AM0.02m | 10:59PM1.06m | 11:27AM-0.00m | 11:40PM1.01m | 12:06PM0.02m | 00:20AM0.94m | ||||||||
 | |  | |  |  |  |  | | | |  | | | | | | | | | | |
 | 4:33 | — | — | 4:35 | — | — | 4:35 | — | — | 4:35 | — | — | 4:37 | — | — | 4:37 | — | — | 4:37 | — | — |
 | — | 6:59 | — | — | 6:58 | — | — | 6:58 | — | — | 6:58 | — | — | 6:57 | — | — | 6:57 | — | — | 6:55 | — |
mm | — | — | — | — | — | 1 | 1 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 25 | 24 | 25 | 25 | 25 | 25 | 25 | 25 | 27 | 29 | 25 | 27 | 27 | 25 | 26 | 26 | 25 | 27 | 27 | 26 |
Feels °C | 25 | 25 | 23 | 24 | 23 | 25 | 29 | 28 | 27 | 29 | 30 | 28 | 29 | 28 | 27 | 27 | 27 | 27 | 29 | 28 | 30 |
Swell 1 Height (m) Direction Period (s) | S 15 | S 16 | SSW 16 | SSW 16 | SSW 17 | SSW 16 | SSW 16 | SSW 15 | SSW 14 | SSW 12 | SSW 12 | SSW 11 | SSW 11 | SSW 10 | SE 10 | SE 10 | SSW 9 | SSW 9 | SSW 9 | SSW 8 | SSE 8 |
| kJ | 1074 | 2141 | 2133 | 2368 | 2296 | 1697 | 1512 | 1079 | 467 | 220 | 206 | 109 | 91 | 85 | 4 | 4 | 28 | 27 | 7 | 7 | 80 |
Swell 2 Height (m) Direction Period (s) | SSW 18 | — | SE 10 | — | — | — | SE 10 | SE 10 | SE 10 | S 4 | SE 10 | SE 9 | SE 9 | SE 9 | S 14 | ESE 9 | SE 10 | SE 9 | ESE 9 | SSE 11 | SSW 8 |
| kJ | 585 | — | 82 | — | — | — | 35 | 32 | 24 | 3 | 4 | 3 | 3 | 3 | 4 | 16 | 4 | 13 | 8 | 12 | 7 |
Swell 3 Height (m) Direction Period (s) | ESE 8 | — | — | — | — | — | — | SE 13 | E 9 | SE 10 | E 7 | SE 12 | SE 12 | SE 12 | S 15 | SE 10 | S 9 | E 9 | S 5 | S 6 | SE 8 |
| kJ | 13 | — | — | — | — | — | — | 7 | 6 | 4 | 1 | 6 | 6 | 6 | 4 | 17 | 2 | 2 | 2 | 2 | 3 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | SSW 4 | SSW 4 | — | — | SSW 3 | — | — | — | — | S 2 | SSW 10 | S 10 | S 3 | — | — | — | — |
| kJ | — | — | — | — | 20 | 19 | — | — | 4 | — | — | — | — | 1 | 102 | 47 | 5 | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 76 | 77 | 27 | 14 | 77 | 27 | 0 | 14 | 12 | 0 | 0 | 0 | 0 | 18 | 14 | 18 | 64 | 64 | 18 | 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.
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