
Surf Forecasts:
Rock Island surf forecast from 20 Jul 2026:
- Best quality surf: Monday 27 Jul, 3PM (local time) - 2.5ft (0.7m), 12s period, S swell with cross-offshore winds.
- Most powerful swell: Monday 27 Jul, 3PM (local time) - 2.5ft (0.7m), 12s period, S swell with 139 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 12AM (local time) - 1ft (0.3m), 11s period with S 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 0.3m and 11s period with a secondary swell of 0.3m and 11s. Another secondary swell of 0.4m and 3s 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 0.7m 12s and forecast to arrive on Monday (Jul 27) at 3PM. 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 2s period and expected on Saturday (Jul 25) 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 | 3PM (Mon 27th Jul) | 2.5ft (0.7m) 12s |
| Most Powerful | 3PM (Mon 27th Jul) | 2.5ft (0.7m) 12s |
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 cookin’ for Rock Island over the next couple of weeks.
Right off the bat, it’s a quiet start. We’re looking at a pretty long stretch of flat to tiny waves with poor conditions through the first week and a bit. From Monday the 20th right through to the morning of the 27th, there’s barely a ripple worth paddling for. The odd little bump shows up, but with no energy in the water and mostly onshore winds, it’s a solid no-go. You’ll be waiting a while.
The first real glimmer of hope comes on Monday the 27th. The afternoon sees a bit of a jump in energy – a moderate 2ft S swell (showing 164 combined energy) with a 12-second period, and a clean cross-off breeze from the ENE. That’s a proper shift in the pattern. The surf will be small but clean, and for a spot that’s been dead quiet, it’s a welcome change.
Now, the standout for the whole period is Tuesday the 28th. That morning, we’ve got a 4ft SSW groundswell with a very long 14-second period. The combined energy kicks up to 745, which is a solid boost. Pair that with a glassy, light offshore wind from the north, and Rock Island is going to be absolutely pristine. This is the best on offer, no question. For a reef break that’s exposed to the south, a long-period SSW swell is a treat. The size is manageable for a beginner, but that long period means the sets will have some punch and the lines will be clean and well-defined. It’s a reef, so it’ll handle that longer period beautifully. The water temp is sitting around 79°F, which is about average for the time of year, so no surprises there.
The next few days after that hold some decent, smaller leftovers. Wednesday the 29th morning has a 3ft SSW swell, still with a 13-second period, and a clean cross-off from the NE. It’s a step down in energy (337) but still a fun, clean option. The crowd situation at Rock Island can be “sometimes” busy, so if you’re heading out on that Tuesday morning, expect a few other locals with the same idea.
After that, the energy fades quickly. The rest of the period into early August is pretty forgettable. We’re back to small, short-period swells, mostly onshore winds, and low energy numbers. The morning of Tuesday the 4th of August has a tiny 0.7ft ESE swell with a very long 15-second period, but with a risk of thunderstorms and only 55 combined energy, it’s not worth getting excited about.
So, to sum it up: the first week is a write-off. The real action is a short, sweet window centered on Tuesday the 28th of July. That’s your standout. Get on it.
Rusty.
Short Range ForecastMostly dry. Warm (max 29°C on Tue morning, min 27°C on Mon night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 35mm), heaviest during Fri night. Warm (max 32°C on Thu morning, min 24°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | |||||||||||||||
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) | SSE 9 | SSE 8 | SSW 4 | SW 4 | ESE 11 | SSW 4 | SSW 4 | SSW 3 | SSW 4 | SSE 10 | SSE 10 | SSE 10 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SSE 15 | SE 15 | SE 15 | S 11 |
Wave Graph | |||||||||||||||||||||
7 | 7 | 9 | 7 | 12 | 11 | 4 | 5 | 7 | 15 | 10 | 12 | 12 | 11 | 18 | 15 | 15 | 22 | 8 | 8 | 22 | |
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 | cross-off | cross-on | off | cross-off | on | cross-off | cross-off | cross-off | cross | on | on | cross-off |
High Tide | 9:04PM1.41m | 9:03AM1.27m | 9:33PM1.40m | 10:14AM1.18m | 10:05PM1.39m | 11:48AM1.12m | 10:43PM1.38m | 1:49PM1.13m | 11:30PM1.38m | 3:34PM1.21m | 00:29AM1.39m | 4:34PM1.30m | 1:35AM1.40m | ||||||||
Low Tide | 2:31PM0.43m | 3:12AM0.65m | 3:07PM0.59m | 4:07AM0.58m | 3:45PM0.75m | 5:11AM0.52m | 4:29PM0.91m | 6:22AM0.44m | 5:30PM1.04m | 7:33AM0.35m | 7:05PM1.13m | 8:36AM0.25m | 8:38PM1.16m | ||||||||
4:41 | — | — | 4:41 | — | — | 4:41 | — | — | 4:43 | — | — | 4:43 | — | — | 4:43 | — | — | 4:45 | — | — | |
— | 6:53 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | 12 | — | 4 | 17 | — | — | 2 | — | — | 18 |
Temp °C | 28 | 28 | 28 | 29 | 28 | 28 | 29 | 28 | 29 | 32 | 31 | 28 | 29 | 28 | 25 | 26 | 26 | 25 | 26 | 27 | 26 |
Feels °C | 32 | 30 | 31 | 34 | 30 | 31 | 34 | 31 | 33 | 35 | 34 | 34 | 33 | 31 | 28 | 29 | 29 | 28 | 28 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | SSE 9 | SSE 8 | SSE 8 | SSW 4 | SSE 8 | S 8 | SSW 4 | SE 8 | SE 11 | SSW 4 | SSE 10 | S 4 | SSE 9 | SSE 9 | SE 11 | SE 10 | SE 10 | SE 10 | SE 15 | SE 15 | S 11 |
7 | 7 | 7 | 3 | 6 | 1 | 3 | 2 | 5 | 4 | 10 | 2 | 8 | 8 | 18 | 15 | 15 | 15 | 8 | 8 | 22 | |
Swell 2 Height (m) Direction Period (s) | S 7 | S 7 | S 7 | SSE 8 | E 11 | SE 11 | SE 8 | SE 11 | S 6 | SSE 10 | S 6 | SSE 10 | S 4 | SE 17 | SSE 7 | SE 16 | SE 16 | SSE 15 | SE 11 | SE 11 | SE 11 |
4 | 1 | 1 | 6 | 2 | 4 | 2 | 5 | 1 | 10 | 1 | 9 | 1 | 11 | 5 | 10 | 10 | 22 | 5 | 5 | 18 | |
Swell 3 Height (m) Direction Period (s) | E 11 | SE 11 | E 11 | E 11 | ESE 11 | — | SE 11 | — | SE 8 | SE 19 | S 8 | SE 18 | SE 18 | SE 11 | SE 16 | S 7 | S 7 | S 8 | SE 5 | SE 9 | SSE 14 |
3 | 5 | 2 | 2 | 12 | — | 4 | — | 2 | 15 | 1 | 12 | 12 | 5 | 10 | 1 | 1 | 1 | 1 | 3 | 20 | |
Wind waves Height (m) Direction Period (s) | S 3 | SSW 3 | SSW 4 | SW 4 | S 4 | SSW 4 | — | SSW 3 | SSW 4 | — | S 5 | — | — | S 4 | ESE 3 | — | — | — | — | SSE 3 | SE 3 |
1 | 3 | 9 | 7 | 6 | 11 | — | 3 | 7 | — | 5 | — | — | 1 | 1 | — | — | — | — | 3 | 2 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 76 | 77 | 77 | 76 | 1424 | 76 | 55 | 853 | 76 | 16 | 74 | 51 | 51 | 18 | 38 | 51 | 51 | 51 | 18 | 76 | 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.










