
Surf Forecasts:
Rock Island surf forecast from 15 Jul 2026:
- Most powerful swell: Sunday 19 Jul, 6AM (local time) - 1.5ft (0.4m), 8s period, SSE swell with 24 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 0.4m 8s and forecast to arrive on Sunday (Jul 19) at 6AM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 6AM (Sun 19th Jul) | 1.5ft (0.4m) 8s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
G'day, Rusty here. Look, I've given Rock Island a good hard look over the next sixteen days, and I'm not gonna lie to you—it's a tough stretch. The first few weeks of the forecast window are pretty much a write-off, with no real surf to speak of. From the 15th of July right through until the morning of the 24th, we're looking at a long, flat run of tiny, weak waves. You're better off keeping the boards in the car and just enjoying the beach, because the swell just isn't showing up. The water temperature is sitting at a pretty average 77° for the time of year, so that's one thing you don't have to worry about.
The first real glimmer of hope comes on the morning of the 24th of July. It's not exactly a classic, but we finally get some energy in the water. We've got a clean, cross-offshore breeze from the east at 6 mph, which is a big plus. The swell is a tiny 1ft from the SE, but with a period of 18 seconds, it's got that long-period groundswell feel. The combined energy is still weak at 71, so it's really just a "surfable but very ordinary" kind of day. For a spot like Rock Island, which is a fairly consistent reef break, you'd hope for more. It's a beginner-friendly spot, but this is small stuff.
The real standout, and the one you should circle in your calendar, is the morning of the 30th of July. This is the pick of the month. We've got a solid 4ft swell from the SE, with a very long period of 15 seconds, pushing a much stronger combined energy of 740. The wind is a clean offshore from the NE at 15 mph, which should groom the waves nicely. The swell direction is from the SE, and Rock Island's optimum direction is S, so it's a little off the perfect angle, but the quality of the wind and size makes it the best on offer. The afternoon holds up too, with a 4ft swell and 861 in combined energy, though the wind swings a bit cross-offshore. This is proper groundswell energy, and with that long period, it'll be lining up nicely on the reef. Just be aware that it's a "sometimes" crowded spot, so you might have some company. This size is fine for intermediate surfers, but it's not a beginner wave.
The morning of the 28th of July is a distant second option, with glassy conditions and a tiny 1ft SE swell, but the energy is still weak and it's barely worth paddling for.
So, to sum it up: the first nine days are a dead zone. The 30th of July is your best bet, with a solid, clean, offshore swell that's worth the wait. The 24th offers a tiny but clean option if you're desperate.
Rusty.
Short Range ForecastModerate rain (total 11mm), heaviest on Fri morning. Warm (max 29°C on Thu afternoon, min 25°C on Fri night). Winds decreasing (fresh winds from the S on Wed afternoon, calm by Thu night). | Days 5-7 Weather SummaryMostly dry. Warm (max 28°C on Tue morning, min 24°C on Sat night). Wind will be generally light. | ||||||||||||||||||||
Wed 15 | Thursday 16 | Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | |||||||||||||||
PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | |
Swell Height Map | |||||||||||||||||||||
Wave Height (m) Direction Period (s) | SW 9 | S 4 | S 5 | S 5 | SSW 8 | SSE 5 | SSE 4 | SSE 9 | SE 9 | SE 8 | SE 8 | SE 8 | SE 8 | S 8 | SSE 9 | S 3 | SSE 8 | SSE 8 | SSE 8 | SSE 8 | S 4 |
Wave Graph | |||||||||||||||||||||
21 | 16 | 11 | 11 | 6 | 9 | 10 | 8 | 12 | 11 | 10 | 16 | 9 | 5 | 7 | 8 | 7 | 7 | 6 | 6 | 2 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | glassy | cross-on | glassy | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | on | on | cross-on | on | cross-on | cross-on | on | on | off |
High Tide | 6:44PM1.45m | 4:50AM1.51m | 7:13PM1.45m | 5:38AM1.50m | 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 | |||||||
Low Tide | 11:40PM1.01m | 12:06PM0.02m | 00:20AM0.94m | 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 | ||||||||
— | — | 4:37 | — | — | 4:39 | — | — | 4:39 | — | — | 4:39 | — | — | 4:41 | — | — | 4:41 | — | — | 4:41 | |
6:57 | — | — | 6:55 | — | — | 6:55 | — | — | 6:54 | — | — | 6:54 | — | — | 6:53 | — | — | 6:53 | — | 6:52 | |
mm | — | — | — | — | 6 | 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | 3 | 4 |
Temp °C | 27 | 26 | 28 | 29 | 27 | 26 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 26 | 27 | 27 | 26 | 28 | 28 | 27 | 28 |
Feels °C | 28 | 26 | 32 | 32 | 31 | 29 | 29 | 29 | 29 | 27 | 27 | 27 | 27 | 28 | 29 | 28 | 28 | 31 | 30 | 29 | 33 |
Swell 1 Height (m) Direction Period (s) | SW 9 | SSW 9 | S 5 | SSW 8 | S 4 | SSW 8 | SSW 8 | SSE 9 | SE 9 | SE 8 | SE 8 | SE 8 | SE 8 | S 8 | SSE 9 | SSE 8 | SSE 8 | SSE 8 | SSE 8 | SSE 8 | S 4 |
21 | 16 | 11 | 7 | 3 | 6 | 6 | 8 | 12 | 11 | 10 | 16 | 9 | 5 | 7 | 7 | 7 | 7 | 6 | 6 | 1 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | SE 9 | SSW 8 | SE 10 | SSW 8 | S 4 | SE 9 | SSW 8 | S 8 | S 8 | S 8 | S 8 | S 8 | SE 8 | S 7 | E 11 | S 8 | S 3 | S 8 | E 11 | SE 8 |
3 | 3 | 7 | 4 | 6 | 1 | 3 | 6 | 1 | 1 | 1 | 5 | 5 | 3 | 1 | 3 | 1 | 1 | 1 | 2 | 2 | |
Swell 3 Height (m) Direction Period (s) | SE 11 | E 11 | SE 9 | SE 8 | SE 10 | SE 10 | E 8 | E 10 | SW 8 | S 9 | S 7 | E 12 | SE 7 | SE 7 | SE 11 | S 9 | E 11 | S 8 | E 11 | E 11 | SW 7 |
5 | 2 | 3 | 3 | 4 | 4 | 1 | 2 | 2 | 2 | 1 | 3 | 2 | 2 | 5 | 2 | 2 | 1 | 2 | 2 | 2 | |
Wind waves Height (m) Direction Period (s) | S 3 | S 4 | — | S 5 | — | SSE 5 | SSE 4 | SSE 4 | SSE 4 | S 3 | SSE 4 | S 3 | S 3 | SSE 4 | S 3 | S 3 | S 3 | — | S 2 | S 3 | — |
5 | 16 | — | 11 | — | 9 | 10 | 6 | 4 | 4 | 4 | 1 | 6 | 4 | 2 | 8 | 3 | — | 1 | 1 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 77 | 77 | 76 | 77 | 77 | 145 | 64 | 77 | 18 | 64 | 64 | 18 | 77 | 51 | 16 | 77 | 55 | 55 | 76 | 76 | 16 |
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.











