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Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
48hr Weather and Surf, issued 2 am Tuesday 12 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
20.7° C
(Which is slightly warmer than usual)How big are the waves at Rock Island today?
The current surf forecast for Rock Island at 9AM is: 0.7m 9s primary swell from a Southeast direction (forecast issued at 02:00am May 12). The wind direction is predicted to be cross-onshore.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (12 May) | 2.5ft (0.7m) | 9s |
| Afternoon (12 May) | 2ft (0.6m) | 9s |
| Evening (12 May) | 2ft (0.6m) | 9s |
Table - waves today at Rock Island. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Short Range ForecastSome drizzle, heaviest during Wed night. Warm (max 23°C on Thu afternoon, min 16°C on Thu night). Wind will be generally light. | ||||||||||||||||||||||||
Tuesday 12 | Wednesday 13 | Thursday 14 | ||||||||||||||||||||||
12 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 12 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 12 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | |
Swell Height Map |    |    |    | |||||||||||||||||||||
SSE 8 | SSE 9 | SSE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 11 | SE 10 | SE 9 | SE 10 | SE 9 | SE 9 | SE 10 | ESE 10 | SE 7 | SE 7 | SE 7 | |
123 | 65 | 67 | 79 | 86 | 71 | 88 | 67 | 51 | 50 | 49 | 50 | 41 | 55 | 44 | 29 | 34 | 29 | 31 | 33 | 9 | 12 | 11 | 12 | |
Wind (km/h) | ||||||||||||||||||||||||
on | on | on | cross-on | on | on | on | cross-on | glassy | glassy | off | cross-off | glassy | on | on | cross-off | off | off | off | cross-off | cross-off | cross-off | cross-on | cross-off | |
High Tide | 1:36AM1.22m | 1:36PM1.09m | 2:10AM1.25m | 2:50PM1.17m | 2:40AM1.28m | 3:50PM1.25m | ||||||||||||||||||
Low Tide | 7:52AM0.65m | 7:43PM0.53m | 8:37AM0.48m | 8:38PM0.60m | 9:17AM0.32m | |||||||||||||||||||
 | |  |  | | | | | |  | | | | | |  | | | | | | | | | |
 | — | 4:39 | — | — | — | — | — | — | — | 4:39 | — | — | — | — | — | — | — | 4:39 | — | — | — | — | — | — |
 | — | — | — | — | — | — | 6:35 | — | — | — | — | — | — | — | 6:36 | — | — | — | — | — | — | — | 6:37 | — |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | |
Temp °C | 18 | 18 | 18 | 18 | 19 | 19 | 19 | 18 | 18 | 17 | 17 | 19 | 20 | 20 | 20 | 20 | 19 | 19 | 18 | 19 | 22 | 23 | 20 | 18 |
14 | 16 | 17 | 17 | 17 | 16 | 17 | 17 | 18 | 17 | 16 | 17 | 18 | 17 | 18 | 18 | 16 | 17 | 17 | 16 | 19 | 20 | 19 | 16 | |
Swell 1 Height (m) Direction Period (s) | SSE 8 | SSE 9 | SSE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 9 | SE 11 | SE 10 | SE 9 | SE 10 | SE 9 | SE 9 | SE 10 | SSE 7 | SE 7 | SE 7 | SE 7 |
 kJ | 123 | 65 | 67 | 79 | 86 | 71 | 88 | 67 | 51 | 50 | 49 | 50 | 41 | 55 | 44 | 29 | 34 | 29 | 31 | 33 | 5 | 12 | 11 | 12 |
Swell 2 Height (m) Direction Period (s) | ESE 10 | — | — | — | — | — | — | — | — | — | S 9 | S 9 | — | S 8 | E 11 | SE 11 | SE 11 | SE 11 | SE 10 | SE 10 | ESE 10 | ESE 10 | ESE 10 | SE 11 |
| kJ | 18 | — | — | — | — | — | — | — | — | — | 2 | 1 | — | 1 | 2 | 5 | 5 | 4 | 4 | 4 | 9 | 9 | 9 | 4 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SE 11 | — | — | — | — | SE 10 | SE 10 | SE 10 | E 9 |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 5 | — | — | — | — | 4 | 4 | 4 | 2 |
Wind waves Height (m) Direction Period (s) | SSE 8 | — | — | — | — | S 3 | — | — | — | — | — | — | — | — | S 3 | — | — | — | — | — | — | — | — | — |
| kJ | 72 | — | — | — | — | 1 | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||||||
Distance (km) | 76 | 38 | 14 | 16 | 18 | 14 | 14 | 14 | 0 | 0 | 0 | 0 | 16 | 18 | 18 | 16 | 38 | 38 | 38 | 38 | 38 | 38 | 64 | 51 |
Best forecast wave conditions in Kanagawa | ||||||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||||||
Header Global | ||||||||||||||||||||||||
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