Surf Forecasts:
Rock Island surf forecast from 26 Jul 2026:
- Best quality surf: Monday 27 Jul, 12AM (local time) - 1ft (0.3m), 11s period, SE swell with offshore winds.
- Most powerful swell: Monday 3 Aug, 3AM (local time) - 1.5ft (0.5m), 16s period, SE swell with 119 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 12AM (local time) - 1ft (0.3m), 11s 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 12AM. 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 11s 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 16s and forecast to arrive on Monday (Aug 03) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 2s period and expected on Monday (Jul 27) at 6AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12AM (Mon 27th Jul) | 1ft (0.3m) 11s |
| Best Surf | 12AM (Mon 27th Jul) | 1ft (0.3m) 11s |
| Most Powerful | 3AM (Mon 3rd Aug) | 1.5ft (0.5m) 16s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Alright, let’s break it down. This forecast for Rock Island starts slow, but there’s a monster on the horizon.
Right now, from Sunday the 26th of July through the first few days of August, the surf is flat to tiny. We’re looking at 1ft to 2ft waves, mixed with short periods or light onshore winds. The water is about 81°F, which is a touch warmer than normal, but the waves are mostly just not there. The combined energy is weak, between 15 and 61. You’ll get some clean mornings, like Monday the 27th and Tuesday the 28th, but the waves are too small to bother with. It’s a bit of a bummer.
Then there’s a big gap. After the 31st of July, the surf drops to almost nothing – 0.3ft to 1ft – with glassy or clean conditions but zero power. From the 3rd of August, the swell period starts to build to 15-16 seconds, and the energy climbs to 120-177 (moderate), but the wave height is still only 2ft to 2ft. The wind is light or glassy in the mornings, but the waves are just too small.
The real action starts on the 5th of August. Wednesday the 5th morning brings a 3ft SE swell with a 17-second period, combined energy of 509 (solid), and clean cross-off wind from the east. That’s a proper groundswell heading for a reef, so it’ll wrap in nice. The true standouts are the 7th and 8th of August.
On Friday the 7th of August morning, expect an 8ft SE swell, 17-second period, and a clean offshore NNE wind at 15 mph. The energy is huge at 3723. This is big, powerful, and clean – for experienced surfers only. But the absolute best is Saturday the 8th of August morning. Rock Island will be going off with a 13ft SE swell, 17-second period, and glassy, calm conditions. The combined energy is a massive 9471. That’s exceptional, world-class reef surf. The crowds can be a factor sometimes, but on a morning like that, it’s worth it. For experts only – this is a serious swell.
After that, Sunday the 9th of August morning still has 13ft from the south, but the period drops to 11 seconds, and it’s glassy again. Still excellent for experienced surfers, but the energy is lower at 4041. The following week, from the 10th, the swell drops back fast, with a 6ft SSW swell on Monday morning but cross-on wind, so it’s marginal.
So, if you want the wave of the forecast, wait for Saturday the 8th of August. That’s the one.
Rusty.
Short Range ForecastModerate rain (total 16mm), heaviest on Sun night. Warm (max 29°C on Wed afternoon, min 23°C on Mon night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 2mm), mostly falling on Fri night. Warm (max 29°C on Fri afternoon, min 26°C on Thu morning). Wind will be generally light. | ||||||||||||||||||
Monday 27 | Tuesday 28 | Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | ||||||||||||||
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 11 | SE 10 | SSW 8 | SE 10 | SE 10 | SE 10 | SSW 8 | S 6 | SSW 7 | SSW 7 | SSW 7 | S 7 | SSW 4 | S 6 | S 6 | SSW 7 | SSW 7 | SE 17 | ESE 16 |
Wave Graph  | |||||||||||||||||||
 kJ | 20 | 16 | 22 | 16 | 15 | 15 | 14 | 29 | 27 | 17 | 18 | 40 | 13 | 22 | 20 | 4 | 4 | 12 | 24 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | cross-off | cross-off | cross-off | glassy | on | cross-off | glassy | on | cross-off | cross-off | on | on | glassy | cross-off | on | cross-off | cross | cross-off |
High Tide | 1:35AM1.40m | 5:13PM1.37m | 2:38AM1.44m | 5:46PM1.42m | 3:36AM1.48m | 6:14PM1.45m | 4:28AM1.51m | 6:41PM1.46m | 5:16AM1.53m | 7:07PM1.47m | 6:03AM1.53m | 7:32PM1.46m | |||||||
Low Tide | 9:30AM0.16m | 9:45PM1.13m | 10:17AM0.10m | 10:34PM1.08m | 11:00AM0.06m | 11:15PM1.00m | 11:39AM0.07m | 11:52PM0.91m | 12:16PM0.11m | 00:29AM0.82m | 12:51PM0.19m | 1:07AM0.73m | |||||||
 |  |  |  | |  | | | | | | | | | | | | |  | |
 | — | 4:46 | — | — | 4:46 | — | — | 4:47 | — | — | 4:48 | — | — | 4:48 | — | — | 4:48 | — | — |
 | 6:50 | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — |
mm | 9 | — | — | — | — | 2 | 5 | — | — | — | — | — | — | — | — | 1 | — | 1 | 2 |
Temp °C | 27 | 26 | 27 | 25 | 25 | 26 | 26 | 27 | 29 | 28 | 28 | 28 | 27 | 28 | 29 | 28 | 28 | 28 | 24 |
Feels °C | 29 | 28 | 29 | 28 | 27 | 28 | 30 | 31 | 31 | 31 | 31 | 30 | 30 | 31 | 33 | 32 | 32 | 31 | 25 |
Swell 1 Height (m) Direction Period (s) | S 9 | SSW 8 | SE 10 | SSW 8 | SSW 9 | SSW 9 | SSW 8 | S 6 | SSW 7 | SSW 7 | SSW 7 | SE 10 | S 4 | S 6 | SE 9 | SSW 7 | SSW 7 | SE 9 | ESE 16 |
| kJ | 14 | 14 | 16 | 14 | 15 | 15 | 14 | 29 | 27 | 17 | 18 | 4 | 8 | 22 | 3 | 4 | 4 | 3 | 24 |
Swell 2 Height (m) Direction Period (s) | SE 11 | SE 10 | SE 14 | SE 10 | SE 10 | SE 10 | SSW 3 | SE 10 | SE 9 | SE 9 | SE 10 | SE 12 | SSW 7 | SE 9 | S 8 | S 4 | SE 8 | SE 17 | SE 10 |
| kJ | 18 | 16 | 8 | 16 | 15 | 15 | 2 | 4 | 3 | 3 | 4 | 6 | 10 | 3 | 1 | 1 | 3 | 12 | 4 |
Swell 3 Height (m) Direction Period (s) | SSE 14 | SE 14 | — | SSE 3 | SE 13 | SE 13 | SSE 10 | SE 13 | SE 12 | SE 12 | SE 12 | S 8 | SE 9 | SE 12 | S 11 | SE 10 | SE 11 | SE 11 | SSW 6 |
| kJ | 20 | 8 | — | 1 | 7 | 7 | 9 | 6 | 6 | 6 | 6 | 1 | 3 | 6 | 3 | 4 | 4 | 4 | 4 |
Wind waves Height (m) Direction Period (s) | — | ENE 2 | SSW 8 | ESE 3 | — | S 2 | SW 3 | — | S 2 | E 2 | — | S 7 | SSW 4 | — | S 6 | — | — | S 2 | S 3 |
| kJ | — | 1 | 22 | 2 | — | 1 | 6 | — | 1 | 1 | — | 40 | 13 | — | 20 | — | — | 1 | 1 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 18 | 0 | 51 | 16 | 38 | 0 | 18 | 38 | 38 | 18 | 51 | 145 | 18 | 55 | 76 | 77 | 76 | 76 | 76 |
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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