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Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
48hr Weather and Surf, issued 2 pm Thursday 30 Apr 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
19.8° C
(Which is slightly warmer than usual)How big are the waves at Rock Island today?
The current surf forecast for Rock Island at 10PM is: 0.4m 7s primary swell from a Southeast direction and 0.1m 10s secondary swell from a Southeast direction (forecast issued at 02:00pm April 30). The wind direction is predicted to be offshore.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (30 Apr) | - | - |
| Afternoon (30 Apr) | 1ft (0.3m) | 8s |
| Evening (30 Apr) | 1ft (0.3m) | 7s |
Table - waves today at Rock Island. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Short Range ForecastHeavy rain (total 38mm), heaviest during Fri morning. Very mild (max 19°C on Sat afternoon, min 11°C on Thu night). Winds decreasing (near gales from the SW on Fri night, calm by Sat night). | ||||||||||||||||||||||||
Thu 30 | Friday 1 | Saturday 2 | Sun 3 | |||||||||||||||||||||
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 | 12 AM | 3 AM | 6 AM | 9 AM | |
Swell Height Map |    |    |    |    | ||||||||||||||||||||
ESE 5 | SE 8 | ESE 6 | SE 7 | SE 7 | SSE 7 | SSE 7 | SSE 8 | SSE 8 | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SW 10 | SSW 10 | SSW 10 | SSW 10 | SW 10 | SW 10 | S 7 | SW 8 | SW 8 | SSW 7 | S 7 | |
2 | 9 | 21 | 8 | 25 | 75 | 101 | 171 | 207 | 277 | 534 | 936 | 627 | 1108 | 331 | 202 | 123 | 50 | 23 | 15 | 18 | 15 | 10 | 8 | |
Wind (km/h) | ||||||||||||||||||||||||
cross-off | off | off | off | off | cross-off | off | off | cross-off | cross-on | on | cross-on | cross-on | cross-on | off | cross-on | on | cross-on | cross-on | glassy | off | off | cross-off | cross-off | |
High Tide | 4:17PM1.30m | 3:52AM1.32m | 5:05PM1.35m | 4:18AM1.35m | 5:51PM1.38m | 4:45AM1.38m | ||||||||||||||||||
Low Tide | 9:51AM0.30m | 10:05PM0.56m | 10:27AM0.16m | 10:43PM0.63m | 11:03AM0.04m | 11:18PM0.71m | ||||||||||||||||||
 | |  |  | | |  |  | | |  |  |  | | | | | |  | | | | | | |
 | — | — | — | — | — | 4:50 | — | — | — | — | — | — | — | 4:50 | — | — | — | — | — | — | — | 4:48 | — | — |
 | — | — | 6:25 | — | — | — | — | — | — | — | 6:25 | — | — | — | — | — | — | — | 6:27 | — | — | — | — | 6:28 |
1 | 1 | — | 1 | 4 | 3 | 7 | 13 | 7 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Temp °C | 14 | 13 | 14 | 14 | 12 | 11 | 11 | 12 | 15 | 15 | 18 | 17 | 16 | 15 | 15 | 17 | 18 | 19 | 19 | 19 | 18 | 18 | 17 | 18 |
10 | 10 | 10 | 10 | 6 | 4 | 5 | 6 | 15 | 15 | 14 | 8 | 9 | 9 | 12 | 15 | 12 | 15 | 18 | 19 | 17 | 16 | 13 | 16 | |
Swell 1 Height (m) Direction Period (s) | ESE 5 | SE 8 | SE 6 | SE 7 | SE 7 | SSE 7 | SSE 7 | SSE 8 | SSE 8 | SSE 9 | SE 9 | — | SE 9 | SSW 8 | SSW 10 | SSW 10 | SSW 10 | S 8 | S 7 | S 7 | SW 8 | SW 8 | SSW 7 | S 7 |
 kJ | 2 | 9 | 5 | 8 | 25 | 75 | 101 | 171 | 207 | 207 | 123 | — | 86 | 361 | 331 | 202 | 123 | 30 | 16 | 15 | 18 | 15 | 9 | 8 |
Swell 2 Height (m) Direction Period (s) | SE 8 | S 5 | SE 9 | SE 10 | — | — | — | N 3 | N 3 | — | — | — | SSE 8 | — | SE 10 | SE 8 | SE 8 | SW 10 | SW 10 | SW 9 | S 7 | ESE 10 | ESE 10 | SW 7 |
| kJ | 2 | 1 | 3 | 4 | — | — | — | 4 | 2 | — | — | — | 26 | — | 4 | 9 | 15 | 50 | 23 | 13 | 4 | 9 | 10 | 2 |
Swell 3 Height (m) Direction Period (s) | S 6 | SE 9 | S 5 | S 5 | — | — | — | — | — | — | — | — | — | — | — | SE 10 | SE 11 | E 9 | SE 9 | SE 9 | SE 9 | S 7 | S 7 | SE 8 |
| kJ | 1 | 3 | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — | 4 | 4 | 14 | 3 | 3 | 3 | 4 | 4 | 3 |
Wind waves Height (m) Direction Period (s) | — | — | ESE 6 | — | NNE 2 | N 3 | N 3 | N 3 | — | SSW 8 | SSW 8 | SSW 8 | SSW 8 | SW 10 | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | 21 | — | 1 | 4 | 3 | 5 | — | 277 | 534 | 936 | 627 | 1108 | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||||||
Distance (km) | 38 | 38 | 794 | 854 | 755 | 17 | 491 | 17 | 0 | 491 | 487 | 487 | 487 | 487 | 0 | 14 | 76 | 136 | 64 | 16 | 38 | 54 | 54 | 16 |
Best forecast wave conditions in Kanagawa | ||||||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||||||
Header Global | ||||||||||||||||||||||||
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