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Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
16 Day Weather and Surf, issued 2 pm Thursday 21 May 2026 JSTForecast update in hr min s Forecast update imminent
Rock Island surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Rock Island sea temperature is
20.8° C
(Which is normal for this time of year)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 Thursday (May 21) at 9PM. The primary swell is predicted to be 1.1m and 8s period with a secondary swell of 0.4m and 10s. 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 2.5m 8s and forecast to arrive on Thursday (May 28) at 9AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 4s period and expected on Friday (May 22) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Thu 21st May) | 3.5ft (1.1m) 8s |
| Best Surf | 9PM (Thu 21st May) | 3.5ft (1.1m) 8s |
| Most Powerful | 9AM (Thu 28th May) | 8ft (2.5m) 8s |
Table - best surf conditions forecast for Rock Island over the next 16 days.
Updates in hr min s Forecast update imminent
Short Range ForecastHeavy rain (total 23mm), heaviest during Thu afternoon. Very mild (max 19°C on Sun morning, min 13°C on Fri afternoon). Winds decreasing (strong winds from the N on Fri morning, calm by Sun morning). | Days 5-7 Weather SummaryMostly dry. Warm (max 25°C on Tue afternoon, min 19°C on Sun afternoon). Wind will be generally light. | ||||||||||||||||||||
Thu 21 | Friday 22 | Saturday 23 | Sunday 24 | Monday 25 | Tuesday 26 | Wednesday 27 | |||||||||||||||
PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | |
Swell Height Map |  |  |  |  |  |  |  |  | |||||||||||||
S 7 | S 8 | S 8 | S 7 | S 8 | S 7 | S 7 | SE 6 | SSE 6 | SSE 6 | SSE 7 | SSE 7 | SE 7 | S 7 | S 7 | SSE 6 | SSE 6 | SSE 6 | S 6 | S 7 | S 8 | |
189 | 95 | 57 | 40 | 10 | 4 | 5 | 54 | 24 | 36 | 59 | 31 | 22 | 23 | 15 | 14 | 15 | 22 | 23 | 250 | 745 | |
Wind (km/h) | |||||||||||||||||||||
off | off | off | off | off | off | cross-off | cross-off | cross-off | glassy | off | cross-off | on | glassy | cross-off | cross-on | off | off | cross-off | on | cross-on | |
High Tide | 9:23PM1.28m | 7:05AM1.31m | 10:14PM1.25m | 7:58AM1.23m | 11:05PM1.24m | 9:12AM1.13m | 11:53PM1.23m | 10:52AM1.06m | 00:37AM1.24m | 12:39PM1.06m | 1:15AM1.26m | 2:09PM1.12m | 1:51AM1.29m | ||||||||
Low Tide | 2:07AM0.99m | 2:39PM0.11m | 3:10AM0.97m | 3:31PM0.23m | 4:29AM0.92m | 4:29PM0.36m | 5:51AM0.82m | 5:34PM0.48m | 7:00AM0.68m | 6:41PM0.59m | 7:54AM0.52m | 7:44PM0.68m | 8:41AM0.36m | ||||||||
 |  |  | |  |  | |  | |  | |  | |  | | |  | | |  |  | |
 | — | — | 4:33 | — | — | 4:31 | — | — | 4:31 | — | — | 4:31 | — | — | 4:31 | — | — | 4:30 | — | — | 4:30 |
 | 6:43 | — | — | 6:43 | — | — | 6:44 | — | — | 6:45 | — | — | 6:45 | — | — | 6:45 | — | — | 6:46 | — | 6:47 |
8 | 6 | 2 | 2 | — | — | — | 5 | — | — | — | — | — | — | — | — | — | — | 1 | 25 | 15 | |
Temp °C | 17 | 17 | 15 | 13 | 13 | 15 | 18 | 18 | 19 | 20 | 20 | 23 | 23 | 22 | 24 | 25 | 22 | 23 | 23 | 21 | 21 |
13 | 14 | 8 | 5 | 5 | 10 | 15 | 17 | 20 | 22 | 23 | 25 | 23 | 24 | 24 | 25 | 23 | 23 | 23 | 24 | 18 | |
Swell 1 Height (m) Direction Period (s) | S 7 | S 8 | S 8 | S 7 | S 8 | S 7 | N 3 | SE 6 | SSE 6 | SSE 6 | SSE 7 | SSE 7 | SE 7 | S 7 | S 7 | ESE 8 | SSE 6 | SSE 6 | SE 10 | S 10 | ESE 13 |
 kJ | 189 | 95 | 57 | 40 | 10 | 4 | 1 | 14 | 24 | 36 | 59 | 31 | 22 | 23 | 15 | 6 | 15 | 22 | 4 | 2 | 17 |
Swell 2 Height (m) Direction Period (s) | ESE 10 | SE 9 | SE 10 | SE 11 | E 11 | E 11 | S 7 | SE 12 | E 12 | E 10 | E 8 | E 11 | SSW 7 | SE 7 | ESE 8 | S 12 | SSW 6 | SW 6 | SE 10 | E 14 | E 8 |
| kJ | 38 | 3 | 4 | 4 | 2 | 2 | 4 | 5 | 3 | 2 | 10 | 2 | 5 | 8 | 6 | 3 | 4 | 1 | 4 | 4 | 5 |
Swell 3 Height (m) Direction Period (s) | — | SE 11 | — | SE 10 | E 9 | E 6 | SE 11 | SW 8 | E 10 | E 10 | E 10 | S 9 | E 16 | — | E 15 | S 10 | E 8 | SE 11 | E 14 | — | — |
| kJ | — | 5 | — | 23 | 2 | 1 | 5 | 2 | 2 | 8 | 2 | 2 | 5 | — | 4 | 2 | 1 | 4 | 4 | — | — |
Wind waves Height (m) Direction Period (s) | SW 7 | NE 3 | NNE 3 | NNE 4 | NNE 4 | NNE 4 | NE 3 | SE 6 | — | — | — | — | — | — | — | SSE 6 | — | — | S 6 | S 7 | S 8 |
| kJ | 183 | 1 | 7 | 32 | 19 | 10 | 1 | 54 | — | — | — | — | — | — | — | 14 | — | — | 23 | 250 | 745 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 78 | 4 | 145 | 145 | 552 | 798 | 794 | 0 | 38 | 16 | 0 | 16 | 18 | 38 | 16 | 54 | 16 | 38 | 64 | 18 | 27 |
Best forecast wave conditions in Kanagawa | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Rock Island surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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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