Surf Forecasts:
Rock Island surf forecast from 28 Aug 2026:
- Most powerful swell: Thursday 3 Sep, 12PM (local time) - 3ft (0.9m), 11s period, S swell with 189 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 0.9m 11s and forecast to arrive on Thursday (Sep 03) at 12PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 3s period and expected on Saturday (Sep 05) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 12PM (Thu 3rd Sep) | 3ft (0.9m) 11s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
The Lowdown
Hey folks, Rusty here. Let’s get straight into what’s on the menu for Rock Island.
Alright, I’ll level with ya—this stretch isn’t looking like one for the memory books. We’ve got a whole heap of days where the swell is just too small and the wind is messing with things. The first real sniff of anything worth paddling out for doesn’t show up until Sunday morning, September 6th. That’s a solid week of flat or poor conditions to sit through before we get anything rideable.
So, come Sunday the 6th, early doors, we’ve got a little pulse of swell—2 ft from the SE at 8 seconds. That’s short-period, so it’ll be a bit weak and wonky, but the wind is glassy. Dead flat, no ripples—that’s a big positive. The combined energy is weak (82), so you’ll be hunting for the few that stand up. Rock Island is a reef setup, exposed to the south, and it’s fairly consistent, but this is a day for the small-wave kit. Water temp feels average for this time of year, nothing wild going on.
If you’re a beginner, that glassy window on Sunday the 6th morning is your best bet—it’s small, clean, and forgiving. The crowds can pop up here sometimes, so you might have a few for company.
After that, the swell tries to bump a little mid-week but the wind turns onshore and bloody strong. By Friday the 11th of September, we get a decent offshore wind from the NNE—25 km/h—and a clean surface, but the swell is only 2 ft from the SE with a long period of 13 seconds. That long period (over 11 seconds) means better shaped waves, but at a beach or reef it can break a bit straight. Energy is moderate (103). It’s surfable but nothing to call home about. Saturday the 12th goes backwards again with the same offshore wind but even smaller swell.
Honestly, the standout window is that glassy Sunday morning on the 6th, and maybe a small window on Friday the 11th if you’re desperate. It’s a lean couple of weeks—hang in there.
Rusty.
Short Range ForecastModerate rain (total 13mm), heaviest on Fri night. Warm (max 28°C on Fri night, min 21°C on Sat afternoon). Winds decreasing (fresh winds from the NNE on Sat afternoon, calm by Sun afternoon). | Days 5-7 Weather SummaryLight rain (total 3mm), mostly falling on Mon night. Warm (max 28°C on Tue afternoon, min 26°C on Mon night). Winds increasing (light winds from the SSW on Mon night, fresh winds from the SSW by Thu afternoon). | ||||||||||||||||||
Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | ||||||||||||||
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) | SSW 7 | SSW 7 | SSE 11 | SSW 8 | SSW 8 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSW 10 | SSW 10 | SSW 10 | SSW 9 | S 9 | S 10 | S 10 | SSW 11 | SSW 11 | SSW 10 |
Wave Graph | |||||||||||||||||||
40 | 18 | 12 | 11 | 11 | 10 | 10 | 9 | 9 | 19 | 38 | 35 | 48 | 43 | 65 | 125 | 128 | 93 | 123 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | cross-off | off | off | off | off | off | off | on | on | on | on | on | on | cross-on | on | on | on | on |
High Tide | 5:19AM1.57m | 6:18PM1.49m | 6:04AM1.58m | 6:41PM1.49m | 6:48AM1.55m | 7:03PM1.50m | 7:33AM1.49m | 7:26PM1.50m | 8:22AM1.41m | 7:51PM1.49m | 9:19AM1.31m | 8:17PM1.47m | |||||||
Low Tide | 11:30PM0.73m | 11:54AM0.30m | 00:05AM0.62m | 12:27PM0.39m | 00:39AM0.52m | 12:58PM0.50m | 1:16AM0.45m | 1:29PM0.63m | 1:56AM0.40m | 1:58PM0.77m | 2:40AM0.39m | 2:27PM0.91m | |||||||
— | 5:11 | — | — | 5:11 | — | — | 5:11 | — | — | 5:13 | — | — | 5:13 | — | — | 5:13 | — | — | |
6:15 | — | 6:14 | — | — | 6:12 | — | — | 6:10 | — | — | 6:09 | — | — | 6:07 | — | — | 6:07 | — | |
mm | 6 | 1 | 4 | 2 | — | — | — | — | — | 1 | — | — | — | — | — | 2 | — | — | — |
Temp °C | 28 | 24 | 22 | 21 | 23 | 24 | 24 | 26 | 27 | 27 | 27 | 28 | 27 | 28 | 28 | 27 | 28 | 28 | 27 |
Feels °C | 29 | 26 | 20 | 19 | 24 | 26 | 28 | 29 | 29 | 31 | 31 | 30 | 29 | 29 | 29 | 28 | 28 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | SSW 7 | SSW 7 | SSW 7 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SSW 10 | SSW 10 | SSW 10 | SSW 9 | S 9 | S 10 | S 10 | SSW 11 | SSW 11 | SSW 10 |
40 | 18 | 9 | 11 | 11 | 6 | 6 | 6 | 6 | 19 | 38 | 35 | 48 | 43 | 65 | 125 | 128 | 93 | 123 | |
Swell 2 Height (m) Direction Period (s) | SSE 10 | SSE 11 | SSE 11 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSW 12 | SSE 10 | SE 10 | SE 10 | SSW 12 | SE 10 | SSW 13 | SSE 6 | SE 10 | SE 7 |
9 | 11 | 12 | 10 | 10 | 10 | 10 | 9 | 9 | 15 | 9 | 4 | 4 | 14 | 4 | 18 | 16 | 4 | 22 | |
Swell 3 Height (m) Direction Period (s) | SE 13 | — | SSW 8 | ESE 6 | E 6 | — | E 5 | — | S 10 | SSE 9 | E 12 | E 12 | E 11 | SE 10 | E 10 | SE 11 | SE 10 | ESE 9 | SE 10 |
7 | — | 6 | 6 | 1 | — | 1 | — | 2 | 9 | 11 | 11 | 2 | 4 | 2 | 4 | 4 | 17 | 4 | |
Wind waves Height (m) Direction Period (s) | — | — | NE 2 | NNE 3 | — | — | — | — | — | SSW 3 | — | S 2 | S 3 | — | S 3 | — | — | SSE 7 | — |
— | — | 2 | 1 | — | — | — | — | — | 2 | — | 1 | 1 | — | 3 | — | — | 62 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 51 | 51 | 228 | 54 | 54 | 55 | 55 | 77 | 38 | 17 | 77 | 38 | 76 | 77 | 92 | 92 | 142 | 90 |
Best forecast wave conditions in Kanagawa | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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.











